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Helium atom
Helium atom ground state.
An illustration of the helium atom, depicting the nucleus (pink) and the electron cloud distribution (black). .The nucleus (upper right) in helium-4 is in reality spherically symmetric and closely resembles the electron cloud, although for more complicated nuclei this is not always the case.^ Electrons that are further from the nucleus have more potential energy .

^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

^ It is more accurate to represent the space occupied by electrons as a cloud.

.The black bar is one ångström, equal to 10−10 m or 100,000 fm.^ The amount of energy supplied by one kilowatt (1000 watt ) for 1 hour (3600 seconds), equal to 3 600 000 joule.

^ One mole of a substance is equal to 6.02 X 10 23 (Avogadro's number) particles of the substance.

Classification
Smallest recognized division of a chemical element
Properties
Mass range: 1.67 × 10−27 to 4.52 × 10−25 kg
Electric charge: zero (neutral), or ion charge
Diameter range: 62 pm (He) to 520 pm (Cs) (data page)
Components: Electrons and a compact nucleus of protons and neutrons
.The atom is a basic unit of matter consisting of a dense, central nucleus surrounded by a cloud of negatively charged electrons.^ Similarly, the Cl has a negative charge because it has the electron from the H atom.

^ Protons have a positive charge and electrons have a negative charge.

^ The number of electrons (negatively charged) is equal to the number of protons (positively charged), therefore the overall charge is zero.

.The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons (except in the case of hydrogen-1, which is the only stable nuclide with no neutron).^ While the hydrogen nucleus contains only 1 proton, the deuterium contains 1 proton and 1 neutron, and the tritium contains 1 proton and 2 neutrons.

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

The electrons of an atom are bound to the nucleus by the electromagnetic force. .Likewise, a group of atoms can remain bound to each other, forming a molecule.^ Carbonic acid is a weak acid; at any point in time there are some molecules that are not dissociated and others have dissociated to form hydrogen ions and bicarbonate ions.

^ For example, phosphorous may form 3 bonds with some atoms but 5 with others.

^ Ozone A gas, an alternative form of oxygen in which 3 atoms of oxygen rather than 2 join to form a molecule.

.An atom containing an equal number of protons and electrons is electrically neutral, otherwise it has a positive or negative charge and is an ion.^ Particles with positive charges are attracted to particles with negative charges.

^ The number of electrons (negatively charged) is equal to the number of protons (positively charged), therefore the overall charge is zero.

^ The positive charges on the protons are balanced by a number of negatively-charged electrons in motion around the nucleus.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

.An atom is classified according to the number of protons and neutrons in its nucleus: the number of protons determines the chemical element, and the number of neutrons determine the isotope of the element.^ A single circle represents the nucleus (protons and neutrons) of the atoms.

^ Isotopes are atoms that have the same number of protons and differ only in the number of neutrons.

^ The mass number is the number of protons and neutrons.

[1]
.The name atom comes from the Greek ἄτομος/átomos, α-τεμνω, which means uncuttable, or indivisible, something that cannot be divided further.^ Element : A chemical substance that cannot be divided into simpler substances by chemical means; atomic species with same number of protons (being the atomic number of the element).
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

.The concept of an atom as an indivisible component of matter was first proposed by early Indian and Greek philosophers.^ Atom was first proposed last summer, and still in active development, it has been implemented by a number of early adopters, including Blogger, Typepad, and LiveJournal.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ This is the first of two articles which discusses proposed extensions to the Atom 1.0 Syndication Format.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.In the 17th and 18th centuries, chemists provided a physical basis for this idea by showing that certain substances could not be further broken down by chemical methods.^ Hydrogen and oxygen in the above example cannot be broken down any further because they are elements .

^ As of the early 21st century, the chemical and physical properties of fullerenes are still under heavy study.

^ Both look at a colorful 18th Century England of highwaymen and adventure; both show us ancestors of the central characters of the Time Pool series.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.During the late 19th and early 20th centuries, physicists discovered subatomic components and structure inside the atom, thereby demonstrating that the 'atom' was divisible.^ It is hard to tell if the word "Riddle" in the title links this tale to the Riddle stories that were popular in late 19th Century America; such stories have a similarly experimental narrative structure.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.The principles of quantum mechanics were used to successfully model the atom.^ Protocol Model: Hierarchy extensions to Atom specify operations for creating, updating, and removing AtomPub Collections using existing AtomPub methods and extensions to Atom syntax.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Atom currently consists of "a conceptual model of a resource, a concrete syntax for this model, a syndication and archiving format (the Atom feed format) using this syntax, and an editing protocol using this syntax.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The mechanics of atoms and combination of atoms, handling them not as point particles (as in Newtonian mechanics) but as represented by waves in space, obeying quantum rules.

[2][3]
Relative to everyday experience, atoms are minuscule objects with proportionately tiny masses. .Atoms can only be observed individually using special instruments such as the scanning tunneling microscope.^ Inertial balance an instrument for comparing masses using only their inertia, and not relying on gravity.

^ This element has no ORE semantics and is used only for Atom-specific processing (e.g., detecting duplications among entry documents discovered from different feeds).
  • ORE User Guide - Resource Map Implementation in Atom 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ In the Resource Map Profile of Atom, expressing date-times in UTC is RECOMMENDED. The use of the special UTC designator ("Z") is RECOMMENDED over the notation using a numeric time zone offset.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Over 99.9% of an atom's mass is concentrated in the nucleus,[note 1] with protons and neutrons having roughly equal mass.^ A single circle represents the nucleus (protons and neutrons) of the atoms.

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ Protons and neutrons have a mass of approximately 1 amu.

.Each element has at least one isotope with unstable nuclei that can undergo radioactive decay.^ Some isotopes are unstable and decay (qv) to form isotopes of other elements.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

^ Activation product: A radioactive isotope of an element (e.g.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

^ Radionuclide: A radioactive isotope of an element.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

.This can result in a transmutation that changes the number of protons or neutrons in a nucleus.^ Transmutation: Changing atoms of one element into those of another by neutron bombardment, causing neutron capture and/or fission.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

^ While the hydrogen nucleus contains only 1 proton, the deuterium contains 1 proton and 1 neutron, and the tritium contains 1 proton and 2 neutrons.

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

[4] .Electrons that are bound to atoms possess a set of stable energy levels, or orbitals, and can undergo transitions between them by absorbing or emitting photons that match the energy differences between the levels.^ The different energy levels are also called electron shells .

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Light in the green and blue regions of the spectrum is absorbed by chromium ions, raising the energy of electrons of the ions from the ground state level to the broad F bands (See Figure 13-10).

.The electrons determine the chemical properties of an element, and strongly influence an atom's magnetic properties.^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ The "atom:title" element has semantics and properties as described in the atom:title Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The "atom:logo" element has semantics and properties as described in the atom:icon Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

Contents

History

Various atoms and molecules as depicted in John Dalton's A New System of Chemical Philosophy (1808), one of the earliest scientific works on atomic theory.

Atomism

.The concept that matter is composed of discrete units and cannot be divided into arbitrarily tiny quantities has been around for millennia, but these ideas were founded in abstract, philosophical reasoning rather than experimentation and empirical observation.^ Element : A chemical substance that cannot be divided into simpler substances by chemical means; atomic species with same number of protons (being the atomic number of the element).
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

^ One and a while an idea pops into your head which you just cannot ignore.

.The nature of atoms in philosophy varied considerably over time and between cultures and schools, and often had spiritual elements.^ These elements are often comic, although the Atom is blissfully unaware of this.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ A server MAY change the values of various elements in the Entry, such as the atom:id, atom:updated, and atom:author values, and MAY choose to remove or add other elements and attributes, or change element content and attribute values.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

^ It does have an inventive fight between the Atom and an invisible being, one that shows the humor that the magazine often brought to its hero's exploits.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.Nevertheless, the basic idea of the atom was adopted by scientists thousands of years later because it elegantly explained new discoveries in the field of chemistry.^ Later expanded by Sommerfeld to explain many qualitative features of atoms and their spectra, but quantitative calculations were only possible after wave mechanics was introduced.

^ Today, just over a year later, work nears completion on the second of the two specifications: The Atom Publishing Protocol.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[5]
.The earliest references to the concept of atoms date back to ancient India in the 6th century BCE,[6] appearing first in Jainism.^ "Converting an Atom document to JSON might, at first, appear to be a fairly straightforward task.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ This date-time also shows up as the value of the atom:updated element of first shown atom:entry , indicating no changes occurred to it since its publication.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Rydberg constant A constant appearing in Balmer's formula , first explained by the Bohr model of the hydrogen atom.

[7] .The Nyaya and Vaisheshika schools developed elaborate theories of how atoms combined into more complex objects.^ They do not fall directly into any of the series of Atom stories that Fox had developed up till that time.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ MUST NOT contain more than one atom:link element with a rel attribute value of "alternate" that has the same combination of type and hreflang attribute values.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ In this tale, the Atom decides to accompany the objects on their journey, to see where they go and how they disappear.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

[8] .In the West, the references to atoms emerged a century later from Leucippus, whose student, Democritus, systematized his views.^ The atom:generator element MAY have a "uri" attribute whose value MUST be an IRI reference [RFC3987] .
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ The atom:generator element MAY have a "uri" attribute whose value MUST be an IRI reference [ RFC3987 ].
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ The "href" attribute contains the link's IRI. atom:link elements MUST have a href attribute, whose value MUST be a IRI reference [RFC3987] .
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

.In approximately 450 BCE, Democritus coined the term átomos (Greek: ἄτομος), which means "uncuttable" or "the smallest indivisible particle of matter". Although the Indian and Greek concepts of the atom were based purely on philosophy, modern science has retained the name coined by Democritus.^ Atom: A particle of matter which cannot be broken up by chemical means.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

^ Atom is based heavily on the concepts and experiences with RSS. Special thanks go out to: NetScape, UserLand, RSS-Dev working group, and especially the RSS community!
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Cupertino, Calif.-based Apple is using RSS as a blanket term for both various versions of the RSS format as well as the rival format, Atom, all of which it plans to support.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[5]
Corpuscularianism is the postulate, expounded in the 13th-century by the alchemist Pseudo-Geber (Geber),[9] that all physical bodies possess an inner and outer layer of minute particles or corpuscles.[10] .Corpuscularianism is similar to the theory atomism, except that where atoms were supposed to be indivisible, corpuscles could in principle be divided.^ All the 'atom:id' values begin 'urn:uuid', so you could in principle move a whole publication from one server and directory to another.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

In this manner, for example, it was theorized that mercury could penetrate into metals and modify their inner structure.[11] Corpuscularianism stayed a dominant theory over the next several hundred years and was blended with alchemy by Robert Boyle and Isaac Newton in the 17th century.[10][12] It was used by Newton, for instance, in his development of the corpuscular theory of light.

Origin of scientific theory

.Further progress in the understanding of atoms did not occur until the science of chemistry began to develop.^ In 1965, Fox began to introduce para-psychology, Charles Fort and other pseudo-science into The Atom .
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Oscar D. Dollar, nicknamed Mister Odd, is a catalyst for fantastic coincidences to occur; he seeks the Atom's help to understand this.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.In 1661, natural philosopher Robert Boyle published The Sceptical Chymist in which he argued that matter was composed of various combinations of different "corpuscules" or atoms, rather than the classical elements of air, earth, fire and water.^ MUST NOT contain more than one atom:published element.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:summary element.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Atom Entry elements in Collection Documents SHOULD contain one app:edited element, and MUST NOT contain more than one.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

[13] .In 1789 the term element was defined by the French nobleman and scientific researcher Antoine Lavoisier to mean basic substances that could not be further broken down by the methods of chemistry.^ GData makes extensive use of '@rel' attributes and external metadata elements that are extensions to the basic Atom-defined ones.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The mean anomaly is one of 6 orbital elements defining Keplerian motion.

[14]
.In 1803, English instructor and natural philosopher John Dalton used the concept of atoms to explain why elements always react in a ratio of small whole numbers—the law of multiple proportions—and why certain gases dissolve better in water than others.^ MAY have any number of child elements from namespaces other than the Atom namespace.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The "atom:content" element MUST NOT be used.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.He proposed that each element consists of atoms of a single, unique type, and that these atoms can join together to form chemical compounds.^ These elements MAY be used to convey information about an Atom feed in which the Atom-based Resource Map is contained.
  • ORE User Guide - Resource Map Implementation in Atom 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The two kinds of Atom Documents defined in the specification (Atom Feed Documents and Atom Entry Documents) must be well-formed XML, and are identified using the 'application/atom+xml' media type.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The content of an atom:id element MUST be created in a way that assures uniqueness.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

[15][16] Dalton is considered the originator of modern atomic theory.[17]
.Additional validation of particle theory (and by extension atomic theory) occurred in 1827 when botanist Robert Brown used a microscope to look at dust grains floating in water and discovered that they moved about erratically—a phenomenon that became known as "Brownian motion". J. Desaulx suggested in 1877 that the phenomenon was caused by the thermal motion of water molecules, and in 1905 Albert Einstein produced the first mathematical analysis of the motion.^ Absolute temperature --temperature in degrees centigrade (also known in this case as "degrees Kelvin" K°) measured from the absolute zero of -273.1° C, the temperature at which all atomic and molecular motions are expected to cease.

^ In this document, we advocate the use of Namespace-based Validation Dispatching Language (ISO/IEC 19757-4) for full validation of atom feeds containing extensions.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Unlike "thermal fission" used in most nuclear reactors, where neutrons are first slowed down by multiple collisions, this process will produce a chain reaction only in relatively pure uranium-235 or plutonium.

[18][19][20] .French physicist Jean Perrin used Einstein's work to experimentally determine the mass and dimensions of atoms, thereby conclusively verifying Dalton's atomic theory.^ The Atom Notification Protocol works by POSTing Atom Entries or Atom Feeds to a NotificationURI using HTTP POST. As is the case with the Atom Publishing Protocol, this document does not seek to specify the form of the URIs that are used.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Atomic masses refer to the masses of neutral atoms, including the masses of the electrons and the mass equivalent of their binding energies.

^ In accordance with the charter of the IETF's Atom Publishing Format and Protocol Working Group, the Atom Publishing Protocol is designed for the primary use case of publishing and management of weblog entries.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[21]
A modern periodic table
.In 1869, building upon earlier discoveries by such scientists as Lavoisier, Dmitri Mendeleev published the first functional periodic table.^ Scientists are also working on building very small structures such as the nanorobot (Figure 13-26), which can check out a patient's blood cells.

^ In 1869 the Russian chemist Mendeleyev successfully organized the various chemical elements into a Periodic Table.

^ SearchMonkey comprises three layers: First, Yahoo partner publishers, such as The New York Times, Yelp, eBay and StumbleUpon, share structured data with Yahoo.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[22] .The table itself is a visual representation of the periodic law which states certain chemical properties of elements repeat periodically when arranged by atomic number.^ When listing chemical elements in order of the weight of their atoms, it was observed (by Mendeleev ["Mendeleyev"]) that certain sequences of chemical behavior tended to repeat, The reason, we now know, is that chemical properties of an atom depend largely on the number and arrangement of "outermost" (weakest bound) electrons.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ The regular pattern in the periodic table is related to the states of the electrons in an atom.

Subcomponents and quantum theory

The physicist J. J. Thomson, through his work on cathode rays in 1897, discovered the electron. .These subatomic particles had the same properties, regardless of the type of atom whence they came.^ Poetically, they are linked to the same dwarf star that led to the Atom's origin.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The law of preservation states, "If two particles in a flowing plasma are initially on the same magnetic field line, they continue doing so in the future."

^ MUST NOT contain more than one atom:link element with a rel attribute value of "alternate" that has the same combination of type and hreflang attribute values.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.This universal component of all atoms destroyed the concept of atoms as being indivisible units.^ Later, when the Atom gets trapped in a time loop, and re-lives these events, the sense of being trapped in an infinite loop is all the stronger.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

[23] .Thomson postulated that the low mass, negatively-charged electrons were distributed throughout the atom, possibly rotating in rings, with their charge balanced by the presence of a uniform sea of positive charge.^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

This later became known as the plum pudding model.
.In 1909, Hans Geiger and Ernest Marsden, under the direction of physicist Ernest Rutherford, bombarded a sheet of gold foil with alpha rays—by then known to be positively charged helium atoms—and discovered that a small percentage of these particles were deflected through much larger angles than was predicted using Thomson's proposal.^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ If a Resource Map exists that describes the Aggregation using serialization format other than Atom, it is RECOMMENDED to convey the URI (URI-R) of this other Resource Map using this link .
  • ORE User Guide - Resource Map Implementation in Atom 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ These turn out to make the process be a complete cycle, one that starts at a much earlier point than anyone but the villain realized.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.Rutherford interpreted the gold foil experiment as suggesting that the positive charge of a heavy gold atom and most of its mass was concentrated in a nucleus at the center of the atom—the Rutherford model.^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ The atomic number is the number of positive charges in the atomic nucleus .

^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

[24]
.While experimenting with the products of radioactive decay, in 1913 radiochemist Frederick Soddy discovered that there appeared to be more than one type of atom at each position on the periodic table.^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:icon element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:source element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[25] .The term isotope was coined by Margaret Todd as a suitable name for different atoms that belong to the same element.^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ It was discovered later that not all of the atoms of a particular element have the same mass.

^ Note that the number of electrons associated with the oxygen atom remains the same, there is no loss or gain - it only oxidizes different atoms in the process.

.J.J. Thomson created a technique for separating atom types through his work on ionized gases, which subsequently led to the discovery of stable isotopes.^ For Resource creation, this specification only defines cases where the POST body has an Atom Entry entity declared as an Atom media type ("application/atom+xml"), or a non-Atom entity declared as a non-Atom media type.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

^ Atom proponents since have been pursuing the formation of a working group in the IETF, a first step toward creating a formal standard.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Like RSS, Atom is being created through an informal consensus process by volunteers in the Web developer community at large.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[26]
A Bohr model of the hydrogen atom, showing an electron jumping between fixed orbits and emitting a photon of energy with a specific frequency.
Meanwhile, in 1913, physicist Niels Bohr suggested that the electrons were confined into clearly defined, quantized orbits, and could jump between these, but could not freely spiral inward or outward in intermediate states.[27] .An electron must absorb or emit specific amounts of energy to transition between these fixed orbits.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ That includes x-rays and gamma rays, but also high-energy ions and electrons emitted by radioactive substances, accelerated by laboratory devices or encountered in space (e.g.

^ Although light spreads as an electromagnetic wave , it can be created or absorbed only in discrete amounts of energy, known as photons.

.When the light from a heated material was passed through a prism, it produced a multi-colored spectrum.^ Black body radiation --light or other electromagnetic radiation emitted due to heat by a solid, liquid or dense gas, with no color of its own (hence "black").

^ Spectral color of an emission of light is its place in the rainbow spectrum.

^ Absorption lines Dark lines interrupting a continuous color spectrum, caused by a cool gas between the light source and the observer.

The appearance of fixed lines in this spectrum was successfully explained by these orbital transitions.[28]
Chemical bonds between atoms were now explained, by Gilbert Newton Lewis in 1916, as the interactions between their constituent electrons.[29] .As the chemical properties of the elements were known to largely repeat themselves according to the periodic law,[30] in 1919 the American chemist Irving Langmuir suggested that this could be explained if the electrons in an atom were connected or clustered in some manner.^ The "atom:title" element has semantics and properties as described in the atom:title Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The "atom:logo" element has semantics and properties as described in the atom:icon Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The "atom:rights" element has semantics and properties as described in the atom:rights Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Groups of electrons were thought to occupy a set of electron shells about the nucleus.^ Group 2 elements have one more electron in their outer shells than group 1 elements.

[31]
.The Stern–Gerlach experiment of 1922 provided further evidence of the quantum nature of the atom.^ "Atom Publishing Protocol [ APP ] client implementations require a fair amount of ancillary server-provided data in order to provide a smooth user experience.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ As a highly intellectual woman scientist, she gives further evidence of how respected scholarly women are in The Atom, along with woman lawyer Jean Loring.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.When a beam of silver atoms was passed through a specially shaped magnetic field, the beam was split based on the direction of an atom's angular momentum, or spin.^ Atom is based heavily on the concepts and experiences with RSS. Special thanks go out to: NetScape, UserLand, RSS-Dev working group, and especially the RSS community!
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ It has the following steps: Light shines through a special alloy glass, then the Atom.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The Atom is shrinking; he is not passing through a barrier such as another dimension or time, as is indicated by the large circle tradition.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.As this direction is random, the beam could be expected to spread into a line.^ In the absence of a magnetic field, the charged particles in a plasma move in straight lines and random directions.

.Instead, the beam was split into two parts, depending on whether the atomic spin was oriented up or down.^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

^ Nuclear fission The breaking up of a heavy nucleus in two parts of comparable masses, typically, 1/3 and 2/3 of the original mass, associated with a great release of energy.

^ Like many long Fox stories, this one breaks into two parts, each with its own subject, characters, and resolution.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

[32]
.In 1926, Erwin Schrödinger, using Louis de Broglie's 1924 proposal that particles behave to an extent like waves, developed a mathematical model of the atom that described the electrons as three-dimensional waveforms, rather than point particles.^ If a Resource Map exists that describes the Aggregation using serialization format other than Atom, it is RECOMMENDED to convey the URI (URI-R) of this other Resource Map using this link .
  • ORE User Guide - Resource Map Implementation in Atom 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Category Documents contain lists of categories described using the "atom:category" element from the Atom Syndication Format [RFC4287] .
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]

^ Category Documents Category Documents contain lists of categories described using the "atom:category" element from the Atom Syndication Format [ RFC4287 ].
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.A consequence of using waveforms to describe particles is that it is mathematically impossible to obtain precise values for both the position and momentum of a particle at the same time; this became known as the uncertainty principle, formulated by Werner Heisenberg in 1926. In this concept, for a given accuracy in measuring a position one could only obtain a range of probable values for momentum, and vice versa.^ Particles that repel each other have the same charge; they are both either positive or they are both negative.

^ In addition, as this media type uses the "+xml" convention, it shares the same security considerations as described in [RFC3023] , Section 10 .
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]

^ For hole filling I'm using only one weight factor (FP16 precision stored in the alpha channel) to control interpolation in a simple image pyramid reduction and expansion.

.This model was able to explain observations of atomic behavior that previous models could not, such as certain structural and spectral patterns of atoms larger than hydrogen.^ Water is a polar molecule because the oxygen atom is much more electronegative than the hydrogen atoms, resulting in unequal sharing of electrons.

^ Child elements of atom:entry other than those in the Atom namespace and the ones listed above have no correspondence in the ORE Model , and MAY be ignored by ORE processors.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The white structures in the model of methane below represent hydrogen atoms and the black structure is a carbon atom.

.Thus, the planetary model of the atom was discarded in favor of one that described atomic orbital zones around the nucleus where a given electron is most likely to be observed.^ This is one of the most appealing of the Atom stories.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ As of mid-2005, the two most likely candidates will be RSS 2.0 and Atom 1.0.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

[33][34]
Schematic diagram of a simple mass spectrometer.
.The development of the mass spectrometer allowed the exact mass of atoms to be measured.^ Ray Palmer's old teacher, Professor Alpheus V. Hyatt, had developed the Time Pool, a device that allows the Atom to explore other eras.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.The device uses a magnet to bend the trajectory of a beam of ions, and the amount of deflection is determined by the ratio of an atom's mass to its charge.^ A propulsion device used in long-range space missions, generating its thrust by a beam of positive ions accelerated electrically.

^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

^ Examples are the instrument used for monitoring astronaut mass aboard space station "Skylab" and the sawblade device described in "Stargazers."

.The chemist Francis William Aston used this instrument to show that isotopes had different masses.^ Inertial balance an instrument for comparing masses using only their inertia, and not relying on gravity.

^ Examples are the instrument used for monitoring astronaut mass aboard space station "Skylab" and the sawblade device described in "Stargazers."

.The atomic mass of these isotopes varied by integer amounts, called the whole number rule.^ Atomic mass units are also called daltons.

^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

^ The periodic table (below) is a table showing the atomic symbol, atomic mass, and atomic number of all of the elements.

[35] .The explanation for these different isotopes awaited the discovery of the neutron, a neutral-charged particle with a mass similar to the proton, by the physicist James Chadwick in 1932. Isotopes were then explained as elements with the same number of protons, but different numbers of neutrons within the nucleus.^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ They may convert spontaneously--after seconds, hours or years, depends on the type of isotope--into other elements; for instance if a neutron in their nucleus converts to a proton, plus and electron which is ejected.

[36]

Fission, high energy physics and condensed matter

.In 1938, the German chemist Otto Hahn, a student of Rutherford, directed neutrons onto uranium atoms expecting to get transuranium elements.^ Add atom:host as child element of atom:entry, per chairs' direction (PacePersonConstruct).
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

Instead, his chemical experiments showed barium as a product.[37] .A year later, Lise Meitner and her nephew Otto Frisch verified that Hahn's result were the first experimental nuclear fission.^ Hydrogen bomb A type of extremely large nuclear bomb, releasing fusion energy of heavy hydrogen (or in later versions, lithium) as well as fission energy of plutonium and uranium.

[38][39] In 1944, Hahn received the Nobel prize in chemistry in which, despite the efforts of Hahn, the contributions of Meitner and Frisch were not recognized.[40]
.In the 1950s, the development of improved particle accelerators and particle detectors allowed scientists to study the impacts of atoms moving at high energies.^ That includes x-rays and gamma rays, but also high-energy ions and electrons emitted by radioactive substances, accelerated by laboratory devices or encountered in space (e.g.

^ Solar energetic particles -- high energy particles occasionally emitted from active areas on the Sun, associated with solar flares and coronal mass ejections .

^ The emissions of radio waves and light from this nebula suggest the presence of high energy particles.

[41] Neutrons and protons were found to be hadrons, or composites of smaller particles called quarks. .Standard models of nuclear physics were developed that successfully explained the properties of the nucleus in terms of these sub-atomic particles and the forces that govern their interactions.^ Nuclear forces The short-range forces acting on protons and neutrons in atomic nuclei.

[42]
.Around 1985, Steven Chu and co-workers at Bell Labs developed a technique for lowering the temperatures of atoms using lasers.^ The basic editing model hasn't changed [in recent drafts]: we use the four basic methods of HTTP (GET, PUT, POST, and DELETE) to shuffle Atom Entries around.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ In addition to the XML syntax, Atom is also being developed in RDF form using Web Ontology Language (OWL).
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.In the same year, a team led by William D. Phillips managed to contain atoms of sodium in a magnetic trap.^ Poetically, they are linked to the same dwarf star that led to the Atom's origin.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ MUST NOT contain more than one atom:link element with a rel attribute value of "alternate" that has the same combination of type and hreflang attribute values.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ An atom:entry MUST NOT contain more than one atom:link element with a rel attribute value of "edit-media" that has the same "type" and "hreflang" attribute values.
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.The combination of these two techniques and a method based on the Doppler effect, developed by Claude Cohen-Tannoudji and his group, allows small numbers of atoms to be cooled to several microkelvin.^ The advent of these characters is welcome: it allows the Atom to start genuinely sharing his work with others.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The Google Base Data API is now freely available from Google, allowing third party developers to have applications that can interact with Google Base...
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Atom-based Resource Maps may be appealing to a number of application domains because of their simplicity and the existence of standard Web feed technology.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

This allows the atoms to be studied with great precision, and later led to the Nobel prize-winning discovery of Bose-Einstein condensation.[43]
Historically, single atoms have been prohibitively small for scientific applications. .Recently, devices have been constructed that use a single metal atom connected through organic ligands to construct a single electron transistor.^ The "atom:updated" element is a Date construct indicating the most recent instant in time when an Atom Feed or Atom Entry was modified in a way the authoring authority considers significant.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Electronic signals are used in this story to extend the Atom's telephone trick.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The basic editing model hasn't changed [in recent drafts]: we use the four basic methods of HTTP (GET, PUT, POST, and DELETE) to shuffle Atom Entries around.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[44] .Experiments have been carried out by trapping and slowing single atoms using laser cooling in a cavity to gain a better physical understanding of matter.^ Atom is based heavily on the concepts and experiences with RSS. Special thanks go out to: NetScape, UserLand, RSS-Dev working group, and especially the RSS community!
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Because the data format is constrained — every entry has a title, entry, id, and content/summary — I can use an Atom feed from any type of application and get some useful information out of it...
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[45]

Components

Subatomic particles

.Though the word atom originally denoted a particle that cannot be cut into smaller particles, in modern scientific usage the atom is composed of various subatomic particles.^ Oh, and the Kool Erlang Kids are getting into the act: Atom-PubSub module for ejabberd (Hmm, I dislike 'Atom PubSub' and all its orthographic variations).
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Originally an RSS replacement, Atom Spins into the Nucleus of the Conversational Web."
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The scene where Jean summons the Atom is also a close variation on the original.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.The constituent particles of an atom are the electron, the proton and the neutron.^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

.However, the hydrogen-1 atom has no neutrons and a positive hydrogen ion has no electrons.^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

.The electron is by far the least massive of these particles at 9.11 × 10−31 kg, with a negative electrical charge and a size that is too small to be measured using available techniques.^ Electron --a lightweight particle, carrying a negative electric charge and found in all atoms.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

^ Ballistic pendulum -- A device often used for measuring the energy of motion of a bullet, adapted by Goddard to measure the thrust of small rockets with various nozzles.

[46] .Protons have a positive charge and a mass 1,836 times that of the electron, at 1.6726 × 10−27 kg, although this can be reduced by changes to the energy binding the proton into an atom.^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ They do not fall directly into any of the series of Atom stories that Fox had developed up till that time.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

.Neutrons have no electrical charge and have a free mass of 1,839 times the mass of electrons,[47] or 1.6929 × 10−27 kg.^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

^ Electron --a lightweight particle, carrying a negative electric charge and found in all atoms.

^ Plasma --a gas containing free ions and electrons , and therefore capable of conducting electric currents.

.Neutrons and protons have comparable dimensions—on the order of 2.5 × 10−15 m—although the 'surface' of these particles is not sharply defined.^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

[48]
.In the Standard Model of physics, both protons and neutrons are composed of elementary particles called quarks.^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

.The quark belongs to the fermion group of particles, and is one of the two basic constituents of matter—the other being the lepton, of which the electron is an example.^ This tale has two groups of crooks, one of which is practicing high tech based manipulation on the other.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Ion --usually, an atom from which one or more electrons have been torn off, leaving a positively charged particle.

^ One of the basic modes of electron wave functions in an atom, defining energy levels etc.

.There are six types of quarks, each having a fractional electric charge of either +2/3 or −1/3. Protons are composed of two up quarks and one down quark, while a neutron consists of one up quark and two down quarks.^ In the diagram below, there are two Workspaces each describing the IRIs, acceptable media types, and categories for a Collection: Service o- Workspace .
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ Large drops fall down, while small ones, carrying charges of the opposite sign, rise up because the force of gravity pulling them down is overcome by upward-blowing winds.

.This distinction accounts for the difference in mass and charge between the two particles.^ Parallax The angle between the directions in which an object is seen from two different positions.

^ What are the differences between Atom and RSS? Apart from the process used to build the specification, and the rigor of the documentation, there are two main substantive changes.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.The quarks are held together by the strong nuclear force, which is mediated by gluons.^ The energy holding a nucleus together, balancing the attraction of the strong nuclear (attractive) force and the electrical repulsion of a large number of positive protons, confined together in a small space.

^ Stars with masses between those extremes collapse into neutron stars , consisting of extreme dense nuclear matter held together by gravity and nuclear force, with a radius of the order of 10 km.

^ Two types actually exist, the "strong force" which holds nuclei together, and the "weak force" which determines the ratio between the numbers of protons and neutrons.

The gluon is a member of the family of gauge bosons, which are elementary particles that mediate physical forces.[49][50]

Nucleus

The binding energy needed for a nucleon to escape the nucleus, for various isotopes.
.All the bound protons and neutrons in an atom make up a tiny atomic nucleus, and are collectively called nucleons.^ Along with operations on resources, the Atom Protocol provides list-based structures, called Collections, for managing and organising resources, called Members.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Since these are all open standards, marking up your pages using any of these formats makes your content more easily reusable.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Media IRI (Media Resource) The Atom Protocol does not make a distinction between Feeds used for Collections and other Atom Feeds.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

The radius of a nucleus is approximately equal to \begin{smallmatrix}1.07 \sqrt[3]{A}\end{smallmatrix}  fm, where A is the total number of nucleons.[51] .This is much smaller than the radius of the atom, which is on the order of 105 fm.^ However, much less ingenuity is used by the Atom in the tracking than in those stories.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.The nucleons are bound together by a short-ranged attractive potential called the residual strong force.^ The energy holding a nucleus together, balancing the attraction of the strong nuclear (attractive) force and the electrical repulsion of a large number of positive protons, confined together in a small space.

^ Nuclear forces The short-range forces acting on protons and neutrons in atomic nuclei.

^ Two types actually exist, the "strong force" which holds nuclei together, and the "weak force" which determines the ratio between the numbers of protons and neutrons.

.At distances smaller than 2.5 fm this force is much more powerful than the electrostatic force that causes positively charged protons to repel each other.^ Even though that distance is 300 million kilometers, the stars are so much more distant that even for the closest star the parallax is only 3/4 of a second of arc.

^ The laws of physics suggest that fields represent more than a possibility of force being observed, but that they can also transmit energy and momentum, e.g.

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

[52]
.Atoms of the same element have the same number of protons, called the atomic number.^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:link element with a rel attribute value of "alternate" that has the same combination of type and hreflang attribute values.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.Within a single element, the number of neutrons may vary, determining the isotope of that element.^ In this case, the characters in the Base64 encoding MAY be preceded and followed in the atom:content element by white-space, and lines are separated by a single newline (U+000A) character.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The app:collection element MAY contain any number of app:categories elements.
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.The total number of protons and neutrons determine the nuclide.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

^ Two types actually exist, the "strong force" which holds nuclei together, and the "weak force" which determines the ratio between the numbers of protons and neutrons.

.The number of neutrons relative to the protons determines the stability of the nucleus, with certain isotopes undergoing radioactive decay.^ Varieties of nuclei also exist ("isotopes") which have other ratios between their numbers of protons and neutrons, but when the departure from the "most stable ratio" becomes large, neutrons can convert to protons + electrons (or vice versa), producing one form of radioactivity.

^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

[53]
.The neutron and the proton are different types of fermions.^ Two types actually exist, the "strong force" which holds nuclei together, and the "weak force" which determines the ratio between the numbers of protons and neutrons.

.The Pauli exclusion principle is a quantum mechanical effect that prohibits identical fermions, such as multiple protons, from occupying the same quantum physical state at the same time.^ Likewise, the mechanics of combining metadata from multiple instances of the same entry, or from multiple feed documents, is out of the scope of this specification.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ In 1928 this effect explained alpha-radioactivity, and it has since then been applied in the quantum physics of solid matter and elsewhere.

^ Einstein's principle of relativity states that the laws of physics are exactly the same in two frames of reference moving with constant velocity along a straight line relative to each other.

.Thus every proton in the nucleus must occupy a different state, with its own energy level, and the same rule applies to all of the neutrons.^ The following rules apply regarding the atom:rights element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:rights element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The following rules apply regarding the atom:logo element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:logo element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The following rules apply regarding the atom:title element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST contain exactly one atom:title element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

This prohibition does not apply to a proton and neutron occupying the same quantum state.[54]
.For atoms with low atomic numbers, a nucleus that has a different number of protons than neutrons can potentially drop to a lower energy state through a radioactive decay that causes the number of protons and neutrons to more closely match.^ The process always lowers the energy of the nucleus.

^ Binding energy of an atomic nucleus .

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

.As a result, atoms with roughly matching numbers of protons and neutrons are more stable against decay.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ The following rules apply regarding the atom:author element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MAY contain any number of atom:author elements.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

.However, with increasing atomic number, the mutual repulsion of the protons requires an increasing proportion of neutrons to maintain the stability of the nucleus, which modifies this trend.^ However, while the true anomaly changes unevenly--faster during closest approach--the mean anomaly increases steadily, in proportion to time.

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

Thus, there are no stable nuclei with equal proton and neutron numbers above atomic number Z = 20 (calcium); and as Z increases toward the heaviest nuclei, the ratio of neutrons per proton required for stability increases to about 1.5.[54]
.
Illustration of a nuclear fusion process that forms a deuterium nucleus, consisting of a proton and a neutron, from two protons.
^ Two types actually exist, the "strong force" which holds nuclei together, and the "weak force" which determines the ratio between the numbers of protons and neutrons.

^ Fast (nuclear) fission Nuclear fission caused by fast neutrons, directly after they are released by the fission of a heavy nucleus.

^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

A positron (e+)—an antimatter electron—is emitted along with an electron neutrino.
.The number of protons and neutrons in the atomic nucleus can be modified, although this can require very high energies because of the strong force.^ Binding energy of an atomic nucleus .

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

.Nuclear fusion occurs when multiple atomic particles join to form a heavier nucleus, such as through the energetic collision of two nuclei.^ Hydrogen bomb A type of extremely large nuclear bomb, releasing fusion energy of heavy hydrogen (or in later versions, lithium) as well as fission energy of plutonium and uranium.

^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

.For example, at the core of the Sun protons require energies of 3–10 keV to overcome their mutual repulsion—the coulomb barrier—and fuse together into a single nucleus.^ Unit of energy: the ability to overcome one Newton along 1 meter (assuming g = 10 meter/sec 2 , it is also the energy required to lift 1 kg by 0.1 meters).

^ The energy invested by the band, overcoming the electrical repulsion of charges already on the sphere provides the energy for creating the high voltage.

^ The energy holding a nucleus together, balancing the attraction of the strong nuclear (attractive) force and the electrical repulsion of a large number of positive protons, confined together in a small space.

[55] .Nuclear fission is the opposite process, causing a nucleus to split into two smaller nuclei—usually through radioactive decay.^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

^ Nuclear fission The breaking up of a heavy nucleus in two parts of comparable masses, typically, 1/3 and 2/3 of the original mass, associated with a great release of energy.

.The nucleus can also be modified through bombardment by high energy subatomic particles or photons.^ Solar energetic particles -- high energy particles occasionally emitted from active areas on the Sun, associated with solar flares and coronal mass ejections .

^ The emissions of radio waves and light from this nebula suggest the presence of high energy particles.

^ High Energy Particles --charged atomic particles moving rapidly, often at a significant fraction of the speed of light.

.If this modifies the number of protons in a nucleus, the atom changes to a different chemical element.^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Updated = element atom:updated { atomDateConstruct } Publishers MAY change the value of this element over time.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ The "atom:title" element has semantics and properties as described in the atom:title Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[56][57]
.If the mass of the nucleus following a fusion reaction is less than the sum of the masses of the separate particles, then the difference between these two values may be emitted as a type of usable energy (such as a gamma ray, or the kinetic energy of a beta particle), as described by Albert Einstein's mass–energy equivalence formula, E = mc2, where m is the mass loss and c is the speed of light.^ Such elements MAY be used to convey types and relationships pertaining to resources other than the Aggregated Resources that have a direct or indirect relationships with the Aggregation or the Resource Map.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ A value of "application/atom+xml;type=entry" MAY appear in any app:accept list of media ranges and indicates that Atom Entry Documents can be POSTed to the Collection.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]

^ Parallax The angle between the directions in which an object is seen from two different positions.

.This deficit is part of the binding energy of the new nucleus, and it is the non-recoverable loss of the energy which causes the fused particles to remain together in a state which require this energy to separate.^ Binding energy of an atomic nucleus .

^ A server is not required to honor the Slug header, but if yours does, you can use it to control at least part of the URL provided to a new resource.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The fact that the painting depicts a new state links it to the non-objective artists, who depicted spiritual states.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

[58]
.The fusion of two nuclei that create larger nuclei with lower atomic numbers than iron and nickel—a total nucleon number of about 60—is usually an exothermic process that releases more energy than is required to bring them together.^ When the client submits non-Atom-Entry representations to a Collection for creation, two Resources are always created — a Media Entry for the requested Resource, and a Media Link Entry for metadata about the Resource that will appear in the Collection.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ In related confusing news, more than one big company has talked about 'Rolling out APP'.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ When the client submits non-Atom-Entry representations to a Collection for creation, two Resources are always created -- a Media Entry for the requested Resource, and a Media Link Entry for metadata about the Resource that will appear in the Collection.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

[59] .It is this energy-releasing process that makes nuclear fusion in stars a self-sustaining reaction.^ Nuclear fusion appears to be the source of the energy of the Sun and of stars.

^ Heat would have counteracted the star's collapse, but the "Urca process" by which the energy is drained away allows it to proceed very rapidly.

^ Hydrogen bomb A type of extremely large nuclear bomb, releasing fusion energy of heavy hydrogen (or in later versions, lithium) as well as fission energy of plutonium and uranium.

.For heavier nuclei, the binding energy per nucleon in the nucleus begins to decrease.^ Binding energy of an atomic nucleus .

^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

^ Nuclear fission The breaking up of a heavy nucleus in two parts of comparable masses, typically, 1/3 and 2/3 of the original mass, associated with a great release of energy.

.That means fusion processes producing nuclei that have atomic numbers higher than about 26, and atomic masses higher than about 60, is an endothermic process.^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

^ MAY contain any number of rdf:Description elements with a value of their rdf:about attribute equal to a URI other than the URI of the Aggregation (URI-A) or the Atom-based Resource Map (URI-R).
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

.These more massive nuclei can not undergo an energy-producing fusion reaction that can sustain the hydrostatic equilibrium of a star.^ Nuclear fusion appears to be the source of the energy of the Sun and of stars.

^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

[54]

Electron cloud

A potential well, showing the minimum energy V(x) needed to reach each position x. A particle with energy E is constrained to a range of positions between x1 and x2.
The electrons in an atom are attracted to the protons in the nucleus by the electromagnetic force. .This force binds the electrons inside an electrostatic potential well surrounding the smaller nucleus, which means that an external source of energy is needed in order for the electron to escape.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

The closer an electron is to the nucleus, the greater the attractive force. .Hence electrons bound near the center of the potential well require more energy to escape than those at greater separations.^ Providing Textual Content Experience teaches that feeds which contain textual content are in general more useful than those which do not.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Atom Documents MUST be well-formed XML. This specification does not define a DTD for Atom Documents, and hence does not require them to be valid (in the sense used by XML).
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ The laws of physics suggest that fields represent more than a possibility of force being observed, but that they can also transmit energy and momentum, e.g.

.Electrons, like other particles, have properties of both a particle and a wave.^ The property of light (and other electromagnetic radiation), also of atoms, to behave as waves in some situations and as particles in others.

.The electron cloud is a region inside the potential well where each electron forms a type of three-dimensional standing wave—a wave form that does not move relative to the nucleus.^ Atom Documents MUST be well-formed XML. This specification does not define a DTD for Atom Documents, and hence does not require them to be valid (in the sense used by XML).
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ The two kinds of Atom Documents defined in the specification (Atom Feed Documents and Atom Entry Documents) must be well-formed XML, and are identified using the 'application/atom+xml' media type.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ All Atom feeds must be well-formed XML documents, and are identified with the 'application/atom+xml' media type.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.This behavior is defined by an atomic orbital, a mathematical function that characterises the probability that an electron will appear to be at a particular location when its position is measured.^ True anomaly The polar angle of an object in a Kepler orbit, measured from in the orbital plane from the position at closest approach.

^ One of the basic modes of electron wave functions in an atom, defining energy levels etc.

[60] .Only a discrete (or quantized) set of these orbitals exist around the nucleus, as other possible wave patterns will rapidly decay into a more stable form.^ Later expanded by Sommerfeld to explain many qualitative features of atoms and their spectra, but quantitative calculations were only possible after wave mechanics was introduced.

^ A Resource Map is a specialization of a Named Graph [ Named Graph ], which  is a set of triples named by a URI.  This URI makes it possible for other applications to link to or refer to the Resource Map.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ This story does not link these feelings up with a "need to change one's life patterns", as do other tales of this era.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

[61] .Orbitals can have one or more ring or node structures, and they differ from each other in size, shape and orientation.^ Fox shows the scientists interacting; they have effects on each other in a positive way that somewhat recall the way one of Fox's cycles "interferes" with another.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ They are different from the hallucinations in other stories, in that they involve a different perspective by a single character.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The three other elements are three angles which give the orientation in space of its orbital plane, e.g.

[62]
Wave functions of the first five atomic orbitals. The three 2p orbitals each display a single angular node that has an orientation and a minimum at the center.
.Each atomic orbital corresponds to a particular energy level of the electron.^ That was an early clue to the existence of atomic energy levels.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

.The electron can change its state to a higher energy level by absorbing a photon with sufficient energy to boost it into the new quantum state.^ Atompub Status : IESG Processing, IESG Evaluation — AD Followup (New version available, Sub state has been changed to AD Follow up from New ID Needed).
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

.Likewise, through spontaneous emission, an electron in a higher energy state can drop to a lower energy state while radiating the excess energy as a photon.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

^ The energy of a photon is greater the shorter the wavelength--smallest for radio waves , increasingly larger for microwaves, infra-red radiation, visible light and ultra-violet light.

.These characteristic energy values, defined by the differences in the energies of the quantum states, are responsible for atomic spectral lines.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Ritz principle The observation that pairs of frequencies of atomic energy levels often have the same difference, to great precision.

^ Quantum level A discrete level set by the laws of quantum physics, limiting the angular momentum of an atom or its energy to certain well-defined values.

[61]
The amount of energy needed to remove or add an electron—the electron binding energy—is far less than the binding energy of nucleons. .For example, it requires only 13.6 eV to strip a ground-state electron from a hydrogen atom,[63] compared to 2.23 million eV for splitting a deuterium nucleus.^ The only extra requirement is that Atom entries contain a threading element that will be indexed for later queries.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ For example, an Atom Processor could suppress display of duplicate entries by displaying only one entry from a set of entries with identical atom:id values.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

[64] .Atoms are electrically neutral if they have an equal number of protons and electrons.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

^ MAY contain any number of rdf:Description elements with a value of their rdf:about attribute equal to a URI other than the URI of the Aggregation (URI-A) or the Atom-based Resource Map (URI-R).
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Atoms that have either a deficit or a surplus of electrons are called ions.^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

^ Ion --usually, an atom from which one or more electrons have been torn off, leaving a positively charged particle.

^ Particle --in general, a charged component of an atom, that is, an ion or electron.

.Electrons that are farthest from the nucleus may be transferred to other nearby atoms or shared between atoms.^ The advent of these characters is welcome: it allows the Atom to start genuinely sharing his work with others.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Child elements of atom:entry other than those in the Atom namespace and the ones listed above have no correspondence in the ORE Model , and MAY be ignored by ORE processors.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Media IRI (Media Resource) The Atom Protocol does not make a distinction between Feeds used for Collections and other Atom Feeds.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.By this mechanism, atoms are able to bond into molecules and other types of chemical compounds like ionic and covalent network crystals.^ In 1965, Fox began to introduce para-psychology, Charles Fort and other pseudo-science into The Atom .
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Like RSS before it, Atom places the content and metadata of an internet resource into a machine-parsable format, perfect for displaying, filtering, remixing, and archiving.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ For all other values of "type", the content of atom:content MUST be a valid Base64 encoding, as described in [RFC3548], section 3 .
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

[65]
The structure of the cloud varies with the number of electrons present in the cloud. .There exist a number of different methods of electron counting, such as the octet rule and eighteen electron rule.^ Named for French astronomer Louis Lagrange (1736-1813) who first studied them and who showed there existed 5 such points.

^ Modern algebra has expanded this to manipulating symbols represented by letter, following certain rules which may differ from the ones applying to numbers, e.g.

.These tend to be rules of thumb and are not valid across all atoms.^ However, we do not believe that this all-in-one approach provides a reliable basis for full validation of atom and its extensions.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ For all other values of "type", the content of atom:content MUST be a valid Base64 encoding, as described in [RFC3548], section 3 .
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Later, when the Atom gets trapped in a time loop, and re-lives these events, the sense of being trapped in an infinite loop is all the stronger.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

Beginning chemistry students are often told the shell structure is simply 2, 8, 8, 8, 8, 8, 8, [...] to make the teaching process easier. .The actual numbers of electrons per shell in the larger atoms can be considerably different, such as 2, 8, 18, 32, 50, 72, but this complexity is reserved for the more advanced student.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ No significant changes can be made and it is intended that future work be done under a different name; Atom is one example of such work.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ As atoms get heavier, their number of electrons increases: the ones more tightly bound tend to arrange themselves in closed "shells" dictated by rules of quantum physics, and as each shell is filled, the arrangement of outermost electrons may repeat itself.

Properties

Nuclear properties

.By definition, any two atoms with an identical number of protons in their nuclei belong to the same chemical element.^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:link element with a rel attribute value of "alternate" that has the same combination of type and hreflang attribute values.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

.Atoms with equal numbers of protons but a different number of neutrons are different isotopes of the same element.^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The "atom:title" element has semantics and properties as described in the atom:title Element section of [ RFC4287 ] unless specified differently below.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.For example, all hydrogen atoms admit exactly one proton, but isotopes exist with no neutrons hydrogen-1, one neutron (deuterium), two neutrons (tritium) and more than two neutrons.^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:icon element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:source element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

The hydrogen-1 is by far the most common form, and is sometimes called protium.[66] .The known elements form a set of atomic numbers from hydrogen with a single proton up to the 118-proton element ununoctium.^ Proton --an ion of hydrogen and one of the fundamental building blocks from which atomic nuclei are made.

^ Hydrogen spectrum The simplest line spectrum of any element, consisting of a number of separate sequences of lines, the lines of each getting closer and closer together as they approach a limit.

^ Feeds are composed of a number of items, known as "entries", each with an extensible set of attached metadata.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[67] .All known isotopes of elements with atomic numbers greater than 82 are radioactive.^ Rather than invent a plethora of new XML formats, this specification chooses to present a number of XHTML profiles, colloquially known as 'microformats'...
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Absolute temperature --temperature in degrees centigrade (also known in this case as "degrees Kelvin" K°) measured from the absolute zero of -273.1° C, the temperature at which all atomic and molecular motions are expected to cease.

^ The following rules apply regarding the atom:author element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MAY contain any number of atom:author elements.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[68][69]
About 339 nuclides occur naturally on Earth, of which 269 (about 79%) have not been observed to decay.[70] .Of the chemical elements, 80 have one or more stable isotopes.^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Atom Entry elements in Collection Documents SHOULD contain one app:edited element, and MUST NOT contain more than one.
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

^ The following rules apply regarding the atom:rights element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:rights element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Elements 43, 61, and all elements numbered 83 or higher have no stable isotopes.^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

As a rule, there is, for each element, only a handful of stable isotopes, the average being 3.1 stable isotopes per element which has any stable isotopes. .Twenty-seven elements have only a single stable isotope, while the largest number of stable isotopes observed for any element is ten, for the element tin.^ However, unlike the in-reply-to header, the "in-reply-to" element is required to identify the unique identifier of only a single parent resource.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

[71]
.Stability of isotopes is affected by the ratio of protons to neutrons, and also by presence of certain "magic numbers" of neutrons or protons which represent closed and filled quantum shells.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ As atoms get heavier, their number of electrons increases: the ones more tightly bound tend to arrange themselves in closed "shells" dictated by rules of quantum physics, and as each shell is filled, the arrangement of outermost electrons may repeat itself.

^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

.These quantum shells correspond to a set of energy levels within the shell model of the nucleus; filled shells, such as the filled shell of 50 protons for tin, confers unusual stability on the nuclide.^ These atom:link elements have no correspondence in the ORE Model , and MAY be ignored by ORE processors.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

.Of the 250 known stable nuclides, only four have both an odd number of protons and odd number of neutrons: hydrogen-2 (deuterium), lithium-6, boron-10 and nitrogen-14.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ They expel extra protons as "alpha particles", nuclei of helium--two protons and two neutrons, a very stable combination.

^ Varieties of nuclei also exist ("isotopes") which have other ratios between their numbers of protons and neutrons, but when the departure from the "most stable ratio" becomes large, neutrons can convert to protons + electrons (or vice versa), producing one form of radioactivity.

Also, only four naturally occurring, radioactive odd-odd nuclides have a half-life over a billion years: potassium-40, vanadium-50, lanthanum-138 and tantalum-180m. .Most odd-odd nuclei are highly unstable with respect to beta decay, because the decay products are even-even, and are therefore more strongly bound, due to nuclear pairing effects.^ As time goes on, I hope we'll see even more products and services that support Atom and AtomPub from Microsoft.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Elements heavier than lead are often unstable because too many protons in their nuclei repel each other.

[71]

Mass

.Because the large majority of an atom's mass comes from the protons and neutrons, the total number of these particles in an atom is called the mass number.^ Atom-based Resource Maps may be appealing to a number of application domains because of their simplicity and the existence of standard Web feed technology.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

.The mass of an atom at rest is often expressed using the unified atomic mass unit (u), which is also called a Dalton (Da).^ The rights pertaining to the Atom Resource Map are expressed using the atom:rights child element of the atom:feed ; its content is the string "No restrictions on the use of this Atom XML document".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Table 3: The elements of an Atom entry used to express an ORE Resource Map, and the associated RDF Triples .
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ This element MUST be used to convey types and relationships pertaining to the Aggregated Resource that can not be expressed using child elements of atom:entry that are in the Atom namespace.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.This unit is defined as a twelfth of the mass of a free neutral atom of carbon-12, which is approximately 1.66 × 10−27 kg.^ Gregorio & de hOra Expires January 10, 2008 [Page 42] Internet-Draft The Atom Publishing Protocol July 2007 12 .
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Unit of energy: the ability to overcome one Newton along 1 meter (assuming g = 10 meter/sec 2 , it is also the energy required to lift 1 kg by 0.1 meters).

^ Gregorio & de hOra Expires January 10, 2008 [Page 27] Internet-Draft The Atom Publishing Protocol July 2007 9.2.1 .
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

[72] Hydrogen-1, the lightest isotope of hydrogen and the atom with the lowest mass, has an atomic weight of 1.007825 u.[73] .An atom has a mass approximately equal to the mass number times the atomic mass unit.^ The 'at:md' element may occur as a child of atom:feed or atom:entry, and contains any number of RDF statements which must be serialised as RDF/XML. It may occur in a given context any number of times.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ MAY contain any number of rdf:Description elements with a value of their rdf:about attribute equal to a URI other than the URI of the Aggregation (URI-A) or the Atom-based Resource Map (URI-R).
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ A consistent system of units in physics, based on distances measured in meters, mass in kilograms, time in seconds.

[74] The heaviest stable atom is lead-208,[68] with a mass of 207.9766521 u.[75]
.As even the most massive atoms are far too light to work with directly, chemists instead use the unit of moles.^ The term 'Atom' is hopelessly vague, and most people use it to refer the feed format, which is fine.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ This means that most RSS 1.0 and RSS 2.0 modules may be used in Atom..."
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The most common use for both RSS and Atom feeds is as the data dissemination format to promote Weblogs and news sites.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.The mole is defined such that one mole of any element will always have the same number of atoms (about 6.022 × 1023).^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ Intermediaries such as aggregators may need to add an atom:source element to an entry that does not contain its own atom:source element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

.This number was chosen so that if an element has an atomic mass of 1 u, a mole of atoms of that element will have a mass very close to 0.001 kg, or 1 gram.^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The 'at:md' element may occur as a child of atom:feed or atom:entry, and contains any number of RDF statements which must be serialised as RDF/XML. It may occur in a given context any number of times.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ MAY contain any number of additional atom:category elements.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

Because of the definition of the unified atomic mass unit, carbon has an atomic mass of exactly 12 u, and so a mole of carbon atoms weighs exactly 0.012 kg.[72] .Other nuclides have atomic masses and molar masses very close to whole numbers in their usual units, such as hydrogen-1. However, except for carbon-12, they cannot be exactly integer numbers, because the masses of different nuclides are not exact integer ratios of each other, although they do not differ from whole number ratios by more than 1%, and often much less.^ The following rules apply regarding the atom:title element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST contain exactly one atom:title element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The server however has since received a more recent copy than the client's, and responds with a status code of 412 (Precondition Failed).
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Earlier, before such electrons were treated as wave phenomena, an older theory viewed them as tiny orbiting spheres and tried to classify atomic energy levels by assuming they represented different classes of orbits of such spheres.

Size

.Atoms lack a well-defined outer boundary, so the dimensions are usually described in terms of the distances between two nuclei when the two atoms are joined in a chemical bond.^ The distance between two crests of a propagating wave of a single frequency /ν.

^ The two kinds of Atom Documents defined in the specification (Atom Feed Documents and Atom Entry Documents) must be well-formed XML, and are identified using the 'application/atom+xml' media type.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ In general, the mapping leverages the fact that the Atom model distinguishes between two URIs that pertain to an Atom Feed: .
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.The radius varies with the location of an atom on the atomic chart, the type of chemical bond, the number of neighboring atoms (coordination number) and a quantum mechanical property known as spin.^ The mechanics of atoms and combination of atoms, handling them not as point particles (as in Newtonian mechanics) but as represented by waves in space, obeying quantum rules.

^ Atom has a coherent linking model to express a number of different types of links.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

[76] .On the periodic table of the elements, atom size tends to increase when moving down columns, but decrease when moving across rows (left to right).^ The rights pertaining to the Atom Resource Map are expressed using the atom:rights child element of the atom:feed ; its content is the string "No restrictions on the use of this Atom XML document".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The following rules apply regarding the atom:rights element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:rights element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The href attribute value of this atom:link element MUST be the URI of a rights expression pertaining to the Aggregation.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[77] .Consequently, the smallest atom is helium with a radius of 32 pm, while one of the largest is caesium at 225 pm.^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

^ Atom is remarkable for many reasons, but especially in how it has remained simple despite being the product of one of the largest committees that ever assembled itself for a community specification.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[78] .These dimensions are thousands of times smaller than the wavelengths of light (400–700 nm) so they can not be viewed using an optical microscope.^ The overall effect on light containing different wavelengths is like that of a glass prism: the intensity of the light deflected is much smaller than with a prism, but the ability to separate close colors is much better.

^ Usually the triangle is drawn with resting on one of its shorter sides, and these functions are viewed as depending on the bottom acute angle (angle smaller than 90 degrees).

.However, individual atoms can be observed using a scanning tunneling microscope.^ However, much less ingenuity is used by the Atom in the tracking than in those stories.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.Some examples will demonstrate the minuteness of the atom.^ Mark Pilgrim presents draft examples and some of the key concepts in his article "The Atom API," published by XML.com .
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

A typical human hair is about 1 million carbon atoms in width.[79] .A single drop of water contains about 2 sextillion (2 × 1021) atoms of oxygen, and twice the number of hydrogen atoms.^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

^ The 'at:md' element may occur as a child of atom:feed or atom:entry, and contains any number of RDF statements which must be serialised as RDF/XML. It may occur in a given context any number of times.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[80] .A single carat diamond with a mass of 2 × 10-4 kg contains about 10 sextillion (1022) atoms of carbon.^ Collections are represented by Atom Feed documents and contain the IRIs of, and metadata about, their Member Resources.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ MAY contain any number of rdf:Description elements with a value of their rdf:about attribute equal to a URI other than the URI of the Aggregation (URI-A) or the Atom-based Resource Map (URI-R).
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ SHOULD NOT contain more than one rdf:Description element with a value of its rdf:about attribute equal to the URI of the Atom-based Resource Map (URI-R).
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[note .2] If an apple were magnified to the size of the Earth, then the atoms in the apple would be approximately the size of the original apple.^ This story originated the Atom's "telephone trick": his ability to travel anywhere on Earth through the phone lines, at the speed of light.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

[81]

Radioactive decay

This diagram shows the half-life (T½) of various isotopes with Z protons and N neutrons.
.Every element has one or more isotopes that have unstable nuclei that are subject to radioactive decay, causing the nucleus to emit particles or electromagnetic radiation.^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

^ MUST NOT contain more than one atom:summary element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Atom Entry elements in Collection Documents SHOULD contain one app:edited element, and MUST NOT contain more than one.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]

.Radioactivity can occur when the radius of a nucleus is large compared with the radius of the strong force, which only acts over distances on the order of 1 fm.^ The energy holding a nucleus together, balancing the attraction of the strong nuclear (attractive) force and the electrical repulsion of a large number of positive protons, confined together in a small space.

[82]
The most common forms of radioactive decay are:[83][84]
  • Alpha decay is caused when the nucleus emits an alpha particle, which is a helium nucleus consisting of two protons and two neutrons. .The result of the emission is a new element with a lower atomic number.
  • Beta decay is regulated by the weak force, and results from a transformation of a neutron into a proton, or a proton into a neutron.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

    ^ They may convert spontaneously--after seconds, hours or years, depends on the type of isotope--into other elements; for instance if a neutron in their nucleus converts to a proton, plus and electron which is ejected.

    ^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

    The first is accompanied by the emission of an electron and an antineutrino, while the second causes the emission of a positron and a neutrino. .The electron or positron emissions are called beta particles.^ The 3 "classical" types of radioactive emissions are (1) alpha particles , nuclei of helium (2) beta-rays , fast electrons and (3) gamma-rays, high-energy photons.

    .Beta decay either increases or decreases the atomic number of the nucleus by one.
  • Gamma decay results from a change in the energy level of the nucleus to a lower state, resulting in the emission of electromagnetic radiation.^ The process always lowers the energy of the nucleus.

    ^ Binding energy of an atomic nucleus .

    ^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

    This can occur following the emission of an alpha or a beta particle from radioactive decay.
.Other more rare types of radioactive decay include ejection of neutrons or protons or clusters of nucleons from a nucleus, or more than one beta particle, or result (through internal conversion) in production of high-speed electrons which are not beta rays, and high-energy photons which are not gamma rays.^ That includes x-rays and gamma rays, but also high-energy ions and electrons emitted by radioactive substances, accelerated by laboratory devices or encountered in space (e.g.

^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Atom Entry elements in Collection Documents SHOULD contain one app:edited element, and MUST NOT contain more than one.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]

Each radioactive isotope has a characteristic decay time period—the half-life—that is determined by the amount of time needed for half of a sample to decay. This is an exponential decay process that steadily decreases the proportion of the remaining isotope by 50% every half life. Hence after two half-lives have passed only 25% of the isotope will be present, and so forth.[82]

Magnetic moment

.Elementary particles possess an intrinsic quantum mechanical property known as spin.^ The mechanics of atoms and combination of atoms, handling them not as point particles (as in Newtonian mechanics) but as represented by waves in space, obeying quantum rules.

.This is analogous to the angular momentum of an object that is spinning around its center of mass, although strictly speaking these particles are believed to be point-like and cannot be said to be rotating.^ For a mass m rotating around the axis at distance r with velocity v , the angular momentum is mrv .

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Although strictly speaking such a sphere does not exist, it is often used as a convenient tool for mapping the position of stars and other heavenly bodies.

.Spin is measured in units of the reduced Planck constant (ħ), with electrons, protons and neutrons all having spin ½ ħ, or "spin-½". In an atom, electrons in motion around the nucleus possess orbital angular momentum in addition to their spin, while the nucleus itself possesses angular momentum due to its nuclear spin.^ Protons and neutrons also have a (much smaller) spin; proton spin in medicine is the basis of magnetic resonance imaging.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ This is almost entirely an apparent motion: actually, the Moon rotates at an almost constant rate, but by Kepler's laws, its orbital motion around the Earth is not constant.

[85]
.The magnetic field produced by an atom—its magnetic moment—is determined by these various forms of angular momentum, just as a rotating charged object classically produces a magnetic field.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Quantum level A discrete level set by the laws of quantum physics, limiting the angular momentum of an atom or its energy to certain well-defined values.

^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

However, the most dominant contribution comes from spin. .Due to the nature of electrons to obey the Pauli exclusion principle, in which no two electrons may be found in the same quantum state, bound electrons pair up with each other, with one member of each pair in a spin up state and the other in the opposite, spin down state.^ The law of preservation states, "If two particles in a flowing plasma are initially on the same magnetic field line, they continue doing so in the future."

^ One also sees related elements in "The Duel of the Two Adam Stranges" (Mystery in Space #59, May 1960).
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Child elements of atom:entry other than those in the Atom namespace and the ones listed above have no correspondence in the ORE Model , and MAY be ignored by ORE processors.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Thus these spins cancel each other out, reducing the total magnetic dipole moment to zero in some atoms with even number of electrons.^ The advent of these characters is welcome: it allows the Atom to start genuinely sharing his work with others.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Among a number of other features, the service now supports the use of the Atom Publishing Protocol to create and edit posts.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

[86]
.In ferromagnetic elements such as iron, an odd number of electrons leads to an unpaired electron and a net overall magnetic moment.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

.The orbitals of neighboring atoms overlap and a lower energy state is achieved when the spins of unpaired electrons are aligned with each other, a process known as an exchange interaction.^ The process always lowers the energy of the nucleus.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

.When the magnetic moments of ferromagnetic atoms are lined up, the material can produce a measurable macroscopic field.^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

.Paramagnetic materials have atoms with magnetic moments that line up in random directions when no magnetic field is present, but the magnetic moments of the individual atoms line up in the presence of a field.^ Magnetic field lines .

^ The law of preservation states, "If two particles in a flowing plasma are initially on the same magnetic field line, they continue doing so in the future."

^ Magnetic field lines --lines in space, used for visually representing magnetic fields .

[86][87]
.The nucleus of an atom can also have a net spin.^ Originally an RSS replacement, Atom Spins into the Nucleus of the Conversational Web."
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Originally an RSS replacement, Atom is now spinning into the nucleus of the conversational Web.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

Normally these nuclei are aligned in random directions because of thermal equilibrium. .However, for certain elements (such as xenon-129) it is possible to polarize a significant proportion of the nuclear spin states so that they are aligned in the same direction—a condition called hyperpolarization.^ The order of such elements is not significant.
  • ietf-atompub-protocol-17.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Such elements MAY be used to convey types and relationships pertaining to resources other than the Aggregated Resources that have a direct or indirect relationships with the Aggregation or the Resource Map.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Such elements MAY be used to convey types and relationships pertaining to resources (other than the Aggregation and the Resource Map) that have a direct or indirect relationships with the Aggregated Resource.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.This has important applications in magnetic resonance imaging.^ Protons and neutrons also have a (much smaller) spin; proton spin in medicine is the basis of magnetic resonance imaging.

[88][89]

Energy levels

.When an electron is bound to an atom, it has a potential energy that is inversely proportional to its distance from the nucleus.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Every mass exerts a gravitational pull on any other mass, inversely proportional to the square of the distance between them.

^ One of the basic modes of electron wave functions in an atom, defining energy levels etc.

.This is measured by the amount of energy needed to unbind the electron from the atom, and is usually given in units of electronvolts (eV).^ A "kilocalorie" or "big calorie" equals 1000 calories and is the unit usually used in describing the energy content of food.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Calorie -- Unit used in measuring the energy of heat or chemical energy.

.In the quantum mechanical model, a bound electron can only occupy a set of states centered on the nucleus, and each state corresponds to a specific energy level.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Atom-specific metadata pertaining to the Atom entry without correspondence in the ORE Model.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

.The lowest energy state of a bound electron is called the ground state, while an electron at a higher energy level is in an excited state.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Most observed auroral light comes from oxygen atoms, elevated to relatively long-lived "excited" energy levels.

^ One of the basic modes of electron wave functions in an atom, defining energy levels etc.

[90]
.In order for an electron to transition between two different states, it must absorb or emit a photon at an energy matching the difference in the potential energy of those levels.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Parallax The angle between the directions in which an object is seen from two different positions.

^ What are the differences between Atom and RSS? Apart from the process used to build the specification, and the rigor of the documentation, there are two main substantive changes.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.The energy of an emitted photon is proportional to its frequency, so these specific energy levels appear as distinct bands in the electromagnetic spectrum.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Ritz principle The observation that pairs of frequencies of atomic energy levels often have the same difference, to great precision.

^ Its spectrum has similarity to that of hydrogen , but with a more general scheme of energy levels.

[91] .Each element has a characteristic spectrum that can depend on the nuclear charge, subshells filled by electrons, the electromagnetic interactions between the electrons and other factors.^ They may convert spontaneously--after seconds, hours or years, depends on the type of isotope--into other elements; for instance if a neutron in their nucleus converts to a proton, plus and electron which is ejected.

[92]
An example of absorption lines in a spectrum.
.When a continuous spectrum of energy is passed through a gas or plasma, some of the photons are absorbed by atoms, causing electrons to change their energy level.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ In a plasma, magnetic field lines also guide the motion of ions and electrons , and direct the flow of some electric currents.

.Those excited electrons that remain bound to their atom will spontaneously emit this energy as a photon, traveling in a random direction, and so drop back to lower energy levels.^ One of Dr. Light's nicknames is "The Prince of Photons", and the best panel in the story shows the Atom, reduced in size and traveling among numerous spherical photons of light.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

.Thus the atoms behave like a filter that forms a series of dark absorption bands in the energy output.^ Like RSS before it, Atom places the content and metadata of an internet resource into a machine-parsable format, perfect for displaying, filtering, remixing, and archiving.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ When you convert an Atom document into JSON, you take a great deal of information-rich content and serialize it into a drastically simplified form.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The Atom series was at its core a detective comic book, and the Atom often trailed suspects, just like other detectives do.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.(An observer viewing the atoms from a different direction, which does not include the continuous spectrum in the background, will instead see a series of emission lines from the photons emitted by the atoms.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Because we see most events from the Atom's point of view, we are for the first time seeing such a Fox mystery tale from the perspective of its focal point.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ The Atom's involvement is mainly that of an observer; he takes little direct role in the tale.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

) .Spectroscopic measurements of the strength and width of spectral lines allow the composition and physical properties of a substance to be determined.^ Semimajor axis -- a property of an ellipse, equal to half its greatest width, as measured along the line connecting its two foci.

^ It ultimately allowed representing a great number of spectral lines by a much smaller number of energy levels, also tracing which jumps between levels were allowed and which were not.

^ Frame of Reference The system of coordinates (and the objects that determine it) in which motion or any physical effects are calculated or measured.

[93]
.Close examination of the spectral lines reveals that some display a fine structure splitting.^ Moon The natural satellite of the Earth; satellites of other planets are also often called "moons" (uncapitalized) Multiplet A closely spaced group of spectral "lines" (wavelengths), suggesting that a single energy level was split into several closely-lying ones, by some additional factor such as electron spin.

This occurs because of spin-orbit coupling, which is an interaction between the spin and motion of the outermost electron.[94] .When an atom is in an external magnetic field, spectral lines become split into three or more components; a phenomenon called the Zeeman effect.^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

^ Magnetic field lines .

^ The law of preservation states, "If two particles in a flowing plasma are initially on the same magnetic field line, they continue doing so in the future."

.This is caused by the interaction of the magnetic field with the magnetic moment of the atom and its electrons.^ In a plasma, magnetic field lines also guide the motion of ions and electrons , and direct the flow of some electric currents.

^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

.Some atoms can have multiple electron configurations with the same energy level, which thus appear as a single spectral line.^ Moon The natural satellite of the Earth; satellites of other planets are also often called "moons" (uncapitalized) Multiplet A closely spaced group of spectral "lines" (wavelengths), suggesting that a single energy level was split into several closely-lying ones, by some additional factor such as electron spin.

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

.The interaction of the magnetic field with the atom shifts these electron configurations to slightly different energy levels, resulting in multiple spectral lines.^ Magnetic field lines .

^ The law of preservation states, "If two particles in a flowing plasma are initially on the same magnetic field line, they continue doing so in the future."

^ Earlier, before such electrons were treated as wave phenomena, an older theory viewed them as tiny orbiting spheres and tried to classify atomic energy levels by assuming they represented different classes of orbits of such spheres.

[95] .The presence of an external electric field can cause a comparable splitting and shifting of spectral lines by modifying the electron energy levels, a phenomenon called the Stark effect.^ Moon The natural satellite of the Earth; satellites of other planets are also often called "moons" (uncapitalized) Multiplet A closely spaced group of spectral "lines" (wavelengths), suggesting that a single energy level was split into several closely-lying ones, by some additional factor such as electron spin.

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

[96]
.If a bound electron is in an excited state, an interacting photon with the proper energy can cause stimulated emission of a photon with a matching energy level.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Most observed auroral light comes from oxygen atoms, elevated to relatively long-lived "excited" energy levels.

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

.For this to occur, the electron must drop to a lower energy state that has an energy difference matching the energy of the interacting photon.^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ The 3 "classical" types of radioactive emissions are (1) alpha particles , nuclei of helium (2) beta-rays , fast electrons and (3) gamma-rays, high-energy photons.

The emitted photon and the interacting photon will then move off in parallel and with matching phases. That is, the wave patterns of the two photons will be synchronized. .This physical property is used to make lasers, which can emit a coherent beam of light energy in a narrow frequency band.^ Cool gas absorbs light in the same frequencies as it emits when hot, e.g.

^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

[97]

Valence and bonding behavior

.The outermost electron shell of an atom in its uncombined state is known as the valence shell, and the electrons in that shell are called valence electrons.^ As atoms get heavier, their number of electrons increases: the ones more tightly bound tend to arrange themselves in closed "shells" dictated by rules of quantum physics, and as each shell is filled, the arrangement of outermost electrons may repeat itself.

.The number of valence electrons determines the bonding behavior with other atoms.^ Among a number of other features, the service now supports the use of the Atom Publishing Protocol to create and edit posts.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ MAY contain any number of rdf:Description elements with a value of their rdf:about attribute equal to a URI other than the URI of the Aggregation (URI-A) or the Atom-based Resource Map (URI-R).
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MAY have any number of child elements from namespaces other than the Atom namespace.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Atoms tend to chemically react with each other in a manner that will fill (or empty) their outer valence shells.^ As atoms get heavier, their number of electrons increases: the ones more tightly bound tend to arrange themselves in closed "shells" dictated by rules of quantum physics, and as each shell is filled, the arrangement of outermost electrons may repeat itself.

[98] .For example, a transfer of a single electron between atoms is a useful approximation for bonds which form between atoms which have one-electron more than a filled shell, and others which are one-electron short of a full shell, such as occurs in the compound sodium chloride and other chemical ionic salts.^ MUST NOT contain more than one atom:summary element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:published element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Also, because Atom uses XML, such IRIs will always be transferable."
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.However, many elements display multiple valences, or tendencies to share differing numbers of electrons in different compounds.^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

.Thus, chemical bonding between these elements takes many forms of electron-sharing that are more than simple electron transfers.^ MUST NOT contain more than one atom:summary element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The following rules apply regarding the atom:rights element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:rights element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:icon element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

Examples include the element carbon and the organic compounds.[99]
.The chemical elements are often displayed in a periodic table that is laid out to display recurring chemical properties, and elements with the same number of valence electrons form a group that is aligned in the same column of the table.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

^ When listing chemical elements in order of the weight of their atoms, it was observed (by Mendeleev ["Mendeleyev"]) that certain sequences of chemical behavior tended to repeat, The reason, we now know, is that chemical properties of an atom depend largely on the number and arrangement of "outermost" (weakest bound) electrons.

.(The horizontal rows correspond to the filling of a quantum shell of electrons.^ As atoms get heavier, their number of electrons increases: the ones more tightly bound tend to arrange themselves in closed "shells" dictated by rules of quantum physics, and as each shell is filled, the arrangement of outermost electrons may repeat itself.

) .The elements at the far right of the table have their outer shell completely filled with electrons, which results in chemically inert elements known as the noble gases.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

[100][101]

States

Snapshots illustrating the formation of a Bose–Einstein condensate.
.Quantities of atoms are found in different states of matter that depend on the physical conditions, such as temperature and pressure.^ No significant changes can be made and it is intended that future work be done under a different name; Atom is one example of such work.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

By varying the conditions, materials can transition between solids, liquids, gases and plasmas.[102] Within a state, a material can also exist in different phases. An example of this is solid carbon, which can exist as graphite or diamond.[103]
.At temperatures close to absolute zero, atoms can form a Bose–Einstein condensate, at which point quantum mechanical effects, which are normally only observed at the atomic scale, become apparent on a macroscopic scale.^ Later expanded by Sommerfeld to explain many qualitative features of atoms and their spectra, but quantitative calculations were only possible after wave mechanics was introduced.

^ The mechanics of atoms and combination of atoms, handling them not as point particles (as in Newtonian mechanics) but as represented by waves in space, obeying quantum rules.

^ Absolute temperature --temperature in degrees centigrade (also known in this case as "degrees Kelvin" K°) measured from the absolute zero of -273.1° C, the temperature at which all atomic and molecular motions are expected to cease.

[104][105] .This super-cooled collection of atoms then behaves as a single super atom, which may allow fundamental checks of quantum mechanical behavior.^ The "Atom Threading Extensions" document describes a mechanism that allows feeds publishers to express threaded discussions within the Atom Syndication Format (RFC 4287).
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The Atom Syndication Format is an IETF standard for publishing entries (single topics or items) and feeds (collections of topics or items).
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The mechanics of atoms and combination of atoms, handling them not as point particles (as in Newtonian mechanics) but as represented by waves in space, obeying quantum rules.

[106]

Identification

.
Scanning tunneling microscope image showing the individual atoms making up this gold (100) surface.
^ This date-time also shows up as the value of the atom:updated element of first shown atom:entry , indicating no changes occurred to it since its publication.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ This means that when Hawkman shows up in the stories of the Atom or Adam Strange, the existence of space ships had a major implication on the stories.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ It began right in the Atom's origin issue, in "Battle of the Tiny Titans", and also showed up in the first issue of his own magazine, "Master of the Plant World".
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

Reconstruction causes the surface atoms to deviate from the bulk crystal structure and arrange in columns several atoms wide with pits between them.
The scanning tunneling microscope is a device for viewing surfaces at the atomic level. .It uses the quantum tunneling phenomenon, which allows particles to pass through a barrier that would normally be insurmountable.^ Atomic particles sometimes face a barrier which, by Newtonian mechanics, would take too much energy to cross, even though its width is limited.

^ The Atom is shrinking; he is not passing through a barrier such as another dimension or time, as is indicated by the large circle tradition.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ By wave mechanics , the particle's wave has a finite (if small) value outside the barrier, too, giving the particle a finite (if small) probability of materializing there, as if it "tunneled" through.

.Electrons tunnel through the vacuum between two planar metal electrodes, on each of which is an adsorbed atom, providing a tunneling-current density that can be measured.^ In general, the mapping leverages the fact that the Atom model distinguishes between two URIs that pertain to an Atom Feed: .
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ What are the differences between Atom and RSS? Apart from the process used to build the specification, and the rigor of the documentation, there are two main substantive changes.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The Link entity-header field provides a means for describing a relationship between two resources, generally between that of the entity associated with the header and some other resource.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.Scanning one atom (taken as the tip) as it moves past the other (the sample) permits plotting of tip displacement versus lateral separation for a constant current.^ The current ORE Profile of Atom has not taken this approach.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Many news readers support both RSS and Atom, although some support only one or the other.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Child elements of atom:entry other than those in the Atom namespace and the ones listed above have no correspondence in the ORE Model , and MAY be ignored by ORE processors.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

The calculation shows the extent to which scanning-tunneling-microscope images of an individual atom are visible. .It confirms that for low bias, the microscope images the space-averaged dimensions of the electron orbitals across closely packed energy levels—the Fermi level local density of states.^ Spin of an electron , intrinsic angular momentum of an electron, affecting energy levels of atoms and such phenomena as the ordering of elements in the periodic table.

^ Moon The natural satellite of the Earth; satellites of other planets are also often called "moons" (uncapitalized) Multiplet A closely spaced group of spectral "lines" (wavelengths), suggesting that a single energy level was split into several closely-lying ones, by some additional factor such as electron spin.

^ That includes x-rays and gamma rays, but also high-energy ions and electrons emitted by radioactive substances, accelerated by laboratory devices or encountered in space (e.g.

[107][108]
.An atom can be ionized by removing one of its electrons.^ The "atom:deleted-entry" element must contain one "atom:id" element whose value specifies the atom:id of the entry that has been removed.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

^ A "partially ionized plasma" such as the Earth's ionosphere is one that also contains neutral atoms.

.The electric charge causes the trajectory of an atom to bend when it passes through a magnetic field.^ Electromagnetic wave or "electromagnetic radiation"--a combination of oscillating magnetic and electric fields, spreading in wavelike fashion through space at a speed of about 300 000 km.sec.

^ In a plasma, magnetic field lines also guide the motion of ions and electrons , and direct the flow of some electric currents.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

.The radius by which the trajectory of a moving ion is turned by the magnetic field is determined by the mass of the atom.^ In a plasma, magnetic field lines also guide the motion of ions and electrons , and direct the flow of some electric currents.

^ Zeeman effect The splitting of the frequency of light emitted by atoms, when the emission occurs in a strong magnetic field, into two or more closely spaced frequencies.

^ Ray excuses himself, turns into the Atom, and descends the magnet.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

The mass spectrometer uses this principle to measure the mass-to-charge ratio of ions. If a sample contains multiple isotopes, the mass spectrometer can determine the proportion of each isotope in the sample by measuring the intensity of the different beams of ions. .Techniques to vaporize atoms include inductively coupled plasma atomic emission spectroscopy and inductively coupled plasma mass spectrometry, both of which use a plasma to vaporize samples for analysis.^ The most common use for both RSS and Atom feeds is as the data dissemination format to promote Weblogs and news sites.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Cupertino, Calif.-based Apple is using RSS as a blanket term for both various versions of the RSS format as well as the rival format, Atom, all of which it plans to support.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ "Today, RSS 2.0 and Atom are both in use by RSS readers and sites offering syndication.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[109]
.A more area-selective method is electron energy loss spectroscopy, which measures the energy loss of an electron beam within a transmission electron microscope when it interacts with a portion of a sample.^ This rare astronomical event (transits occur in pairs, more than a century apart) was proposed by Edmond Halley as the basis of a method of measuring the astronomical unit .

.The atom-probe tomograph has sub-nanometer resolution in 3-D and can chemically identify individual atoms using time-of-flight mass spectrometry.^ The use of a URI to identify a contributor is RECOMMENDED. atom:entry elements MUST contain exactly one atom:id element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Using the Time Pool, the Atom goes back to 1739 England, where he encounters the notorious robber Dick Turpin.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ In the Resource Map Profile of Atom, expressing date-times in UTC is RECOMMENDED. The use of the special UTC designator ("Z") is RECOMMENDED over the notation using a numeric time zone offset.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[110]
Spectra of excited states can be used to analyze the atomic composition of distant stars. .Specific light wavelengths contained in the observed light from stars can be separated out and related to the quantized transitions in free gas atoms.^ For example, the YouTube Atom Entry links related videos to a separate Atom feed (relative to the entry) with a specially defined '@rel' attribute value...
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Controlled by NVDL scripts, the NVDL engine decomposes atom feeds containing extension elements or attributes into (1) extension-free atom and (2) extensions so that (1) and (2) are validated separately.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The following rules apply regarding the atom:rights element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:rights element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.These colors can be replicated using a gas-discharge lamp containing the same element.^ The use of a URI to identify a contributor is RECOMMENDED. atom:entry elements MUST contain exactly one atom:id element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ It must contain a URI which must be interpreted as a link relation; the first such occurrence of an atom:link element in the same context as its parent element with that relation (in lexical order) will indicate the URI to use as the subject.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ A recommendation regarding the RDF/XML style to be used for these rdf:Description elements is provided in the [ ORE User Guide RDF/XML ].
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[111] .Helium was discovered in this way in the spectrum of the Sun 23 years before it was found on Earth.^ Equinox -- the time of the year (around March 21 and September 23) when the position of the Sun in the sky (following the ecliptic) crosses the celestial equator.

^ For other identities, see here Tropic of Cancer The line of northern latitude 23.5°, north of which the Sun is never at zenith on any day of the year.

^ Such dark lines in the Sun's spectrum were discovered by Joseph Frauenhofer.

[112]

Origin and current state

.Atoms form about 4% of the total energy density of the observable universe, with an average density of about 0.25 atoms/m3.^ Atom provides a universal way that computers can share a base level of information about whatever things they model.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

[113] .Within a galaxy such as the Milky Way, atoms have a much higher concentration, with the density of matter in the interstellar medium (ISM) ranging from 105 to 109 atoms/m3.^ They are now called "galaxies" too, whereas the Milky Way is " our galaxy."

^ Spectral line A narrow range of spectral color, emitted (or absorbed) by a specific atom (or molecule).The energy of its photon corresponds to the difference between two energy levels of the atom, and such photons are emitted when the atom "falls" from the higher level to the lower one.

^ Snell: "While Atom and AtomPub certainly began life as a way of syndicating and publishing Weblog content, it has proven useful for a much broader range of applications.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[114] .The Sun is believed to be inside the Local Bubble, a region of highly ionized gas, so the density in the solar neighborhood is only about 103 atoms/m3.^ Convection is also believed to occur in a certain depth range below the Sun's surface, helping carry away heat from the Sun's core region.

^ One of the things that doesn't get noticed at first about the Atom Syndication Format is that not only are feeds first class documents, but so are entries...
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ "Recently, I was asked for feedback on some technology being built inside Sun which was said to rely on 'Atom Pub/Sub'.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[115] .Stars form from dense clouds in the ISM, and the evolutionary processes of stars result in the steady enrichment of the ISM with elements more massive than hydrogen and helium.^ MUST NOT contain more than one atom:summary element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The following rules apply regarding the atom:rights element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MUST NOT contain more than one atom:rights element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MUST NOT contain more than one atom:icon element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Up to 95% of the Milky Way's atoms are concentrated inside stars and the total mass of atoms forms about 10% of the mass of the galaxy.^ They are now called "galaxies" too, whereas the Milky Way is " our galaxy."

^ The nuclei of atoms are positively charged and contain by far most of their mass (all but about 0.05% or less).

^ Atom provides a universal way that computers can share a base level of information about whatever things they model.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

[116] (The remainder of the mass is an unknown dark matter.[117])

Nucleosynthesis

.Stable protons and electrons appeared one second after the Big Bang.^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

^ Varieties of nuclei also exist ("isotopes") which have other ratios between their numbers of protons and neutrons, but when the departure from the "most stable ratio" becomes large, neutrons can convert to protons + electrons (or vice versa), producing one form of radioactivity.

.During the following three minutes, Big Bang nucleosynthesis produced most of the helium, lithium, and deuterium in the universe, and perhaps some of the beryllium and boron.^ Primordial microwaves A diffuse microwave radiation apparently filling the entire universe, a remnant of gamma rays emitted by the " primordial fireball " in the early universe, following the "Big Bang."

[118][119][120] .The first atoms (complete with bound electrons) were theoretically created 380,000 years after the Big Bang—an epoch called recombination, when the expanding universe cooled enough to allow electrons to become attached to nuclei.^ Primordial microwaves A diffuse microwave radiation apparently filling the entire universe, a remnant of gamma rays emitted by the " primordial fireball " in the early universe, following the "Big Bang."

^ Oddly enough, there is less educational material in the next two Showcase issues of the Atom; but the educational material returns spectacularly with the first issue of The Atom magazine.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

[121] .Since then, atomic nuclei have been combined in stars through the process of nuclear fusion to produce elements up to iron.^ Nuclear fusion appears to be the source of the energy of the Sun and of stars.

^ This date-time also shows up as the value of the atom:updated element of first shown atom:entry , indicating no changes occurred to it since its publication.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Nuclear forces The short-range forces acting on protons and neutrons in atomic nuclei.

[122]
.Isotopes such as lithium-6 are generated in space through cosmic ray spallation.^ Some of his Justice League characters such as Superman and Green Lantern could travel through space on their own power.
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[123] .This occurs when a high-energy proton strikes an atomic nucleus, causing large numbers of nucleons to be ejected.^ Binding energy of an atomic nucleus .

^ The energy holding a nucleus together, balancing the attraction of the strong nuclear (attractive) force and the electrical repulsion of a large number of positive protons, confined together in a small space.

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

.Elements heavier than iron were produced in supernovae through the r-process and in AGB stars through the s-process, both of which involve the capture of neutrons by atomic nuclei.^ Isotopes --Variants found in many chemical elements, differing slightly in weight because the number of neutrons in their nuclei differ.

^ Nuclear forces The short-range forces acting on protons and neutrons in atomic nuclei.

^ Radioactivity --Instability of some atomic nuclei, causing them to change spontaneously to a lower energy level or to modify the number of protons and neutrons they contain.

[124] .Elements such as lead formed largely through the radioactive decay of heavier elements.^ The Atom is shrinking; he is not passing through a barrier such as another dimension or time, as is indicated by the large circle tradition.
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[125]

Earth

.Most of the atoms that make up the Earth and its inhabitants were present in their current form in the nebula that collapsed out of a molecular cloud to form the Solar System.^ Like most sf stories in the Atom, it concerns new technological events, taking place on Earth close to Ray's Ivy Town home.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Make sure to pick up the latest version; as of the time of this writing, draft 6 was the most current one.
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^ Mean Sun-Earth distance, used as scaling distance in the solar system.

The rest are the result of radioactive decay, and their relative proportion can be used to determine the age of the Earth through radiometric dating.[126][127] .Most of the helium in the crust of the Earth (about 99% of the helium from gas wells, as shown by its lower abundance of helium-3) is a product of alpha decay.^ Alpha radioactivity , The radioactive decay of heavy nuclei by emission of an alpha particle, a nucleus of helium.

[128]
.There are a few trace atoms on Earth that were not present at the beginning (i.e., not "primordial"), nor are results of radioactive decay.^ The Earth 2 Atom begins to experience unusual powers.
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Carbon-14 is continuously generated by cosmic rays in the atmosphere.[129] .Some atoms on Earth have been artificially generated either deliberately or as by-products of nuclear reactors or explosions.^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

[130][131] .Of the transuranic elements—those with atomic numbers greater than 92—only plutonium and neptunium occur naturally on Earth.^ Child elements of atom:entry other than those in the Atom namespace and the ones listed above have no correspondence in the ORE Model , and MAY be ignored by ORE processors.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The 'at:md' element may occur as a child of atom:feed or atom:entry, and contains any number of RDF statements which must be serialised as RDF/XML. It may occur in a given context any number of times.
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^ The following rules apply regarding the atom:author element; rules that are more specific than the ones of [ RFC4287 ] are shown in italic: atom:feed elements MAY contain any number of atom:author elements.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[132][133] .Transuranic elements have radioactive lifetimes shorter than the current age of the Earth[134] and thus identifiable quantities of these elements have long since decayed, with the exception of traces of plutonium-244 possibly deposited by cosmic dust.^ If the magnetic properties of the Earth came from it being a giant magnet (rather than from electric currents in its interior) then the magnetic pole close to its northern geographic pole would in fact be an "S" pole or "south seeking" pole--since it attracts the north-seeking pole of the compass needle!

^ Sidereal day The true period of rotation of the Earth, about 4 minutes shorter than 24 hours.

^ Usually the triangle is drawn with resting on one of its shorter sides, and these functions are viewed as depending on the bottom acute angle (angle smaller than 90 degrees).

[126] .Natural deposits of plutonium and neptunium are produced by neutron capture in uranium ore.^ Unlike "thermal fission" used in most nuclear reactors, where neutrons are first slowed down by multiple collisions, this process will produce a chain reaction only in relatively pure uranium-235 or plutonium.

[135]
.The Earth contains approximately 1.33 × 1050 atoms.^ A "partially ionized plasma" such as the Earth's ionosphere is one that also contains neutral atoms.

[136] .In the planet's atmosphere, small numbers of independent atoms of noble gases exist, such as argon and neon.^ Building on a RESTful specification such as Atom while leveraging the design of existing services like GData have ensured a solid foundation on which to build.
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^ Some gases which constitute only a small portion of the atmosphere--water vapor, CO 2 (carbon dioxide) and CH 4 (methane)--are major contributors to the greenhouse effect.

The remaining 99% of the atmosphere is bound in the form of molecules, including carbon dioxide and diatomic oxygen and nitrogen. .At the surface of the Earth, atoms combine to form various compounds, including water, salt, silicates and oxides.^ We combined a variation of atom.rnc and three schemas for atom extensions thereby successfully providing full validation.
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^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

^ One might wonder whether atom.rnc and extension schemas can be combined to form a single RELAX NG schema against which atom feeds containing extensions are fully validated.
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.Atoms can also combine to create materials that do not consist of discrete molecules, including crystals and liquid or solid metals.^ They then create NVDL scripts for combining these schemas and atom.rnc.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ All substances consist of atoms, usually combined chemically into molecules.

[137][138] .This atomic matter forms networked arrangements that lack the particular type of small-scale interrupted order associated with molecular matter.^ Quantum physics The laws obeyed by matter on the atomic scale, involving Planck's constant and wave properties of matter.

[139]

Rare and theoretical forms

.While isotopes with atomic numbers higher than lead (82) are known to be radioactive, an "island of stability" has been proposed for some elements with atomic numbers above 103. These superheavy elements may have a nucleus that is relatively stable against radioactive decay.^ MAY have any number of child elements from namespaces other than the Atom namespace.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Such elements MAY be used to convey types and relationships pertaining to resources other than the Aggregated Resources that have a direct or indirect relationships with the Aggregation or the Resource Map.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

[140] .The most likely candidate for a stable superheavy atom, unbihexium, has 126 protons and 184 neutrons.^ As of mid-2005, the two most likely candidates will be RSS 2.0 and Atom 1.0.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Like most sf stories in the Atom, it concerns new technological events, taking place on Earth close to Ray's Ivy Town home.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ Among light nuclei (helium, carbon, nitrogen), the ones that are most stable contain equal numbers of protons and neutrons.

[141]
.Each particle of matter has a corresponding antimatter particle with the opposite electrical charge.^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

^ The work performed by separating opposite charge ends up as electric energy, at high voltages.

^ Electron --a lightweight particle, carrying a negative electric charge and found in all atoms.

.Thus, the positron is a positively charged antielectron and the antiproton is a negatively charged equivalent of a proton.^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

When a matter and corresponding antimatter particle meet, they annihilate each other. Because of this, along with an imbalance between the number of matter and antimatter particles, the latter are rare in the universe. (The first causes of this imbalance is not yet fully understood, although the baryogenesis theories may offer an explanation.) As a result, no antimatter atoms have been discovered in nature.[142][143] However, in 1996, antihydrogen, the antimatter counterpart of hydrogen, was synthesized at the CERN laboratory in Geneva.[144][145]
.Other exotic atoms have been created by replacing one of the protons, neutrons or electrons with other particles that have the same charge.^ The small concentration of protons and neutrons, positively charged, at the center of atoms.

^ Neutron A particle found in the nuclei of atoms, similar to a proton but with no electric charge.

^ Among a number of other features, the service now supports the use of the Atom Publishing Protocol to create and edit posts.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.For example, an electron can be replaced by a more massive muon, forming a muonic atom.^ "Negative ions" are atoms which have acquired one or more extra electrons, and clusters of atoms can also become ions.

^ Nuclear fusion The process of releasing energy by combining hydrogen atoms to form helium, or more generally, to combine light nuclei into heavier ones.

^ Ion --usually, an atom from which one or more electrons have been torn off, leaving a positively charged particle.

.These types of atoms can be used to test the fundamental predictions of physics.^ This element MUST be used to convey types and relationships pertaining to the Aggregated Resource that can not be expressed using child elements of atom:entry that are in the Atom namespace.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ What is needed is guidance — essentially, an implementors guide to Atom for these use cases.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The use of a URI to identify an author is RECOMMENDED. atom:feed elements MUST contain exactly one atom:category element typing the Atom Feed as an Aggregation.
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[146][147][148]

See also

Notes

  1. ^ Most isotopes have more nucleons than electrons. In the case of hydrogen-1, with a single electron and nucleon, the proton is \begin{smallmatrix}\frac{1836}{1837} \approx 0.9995\end{smallmatrix}, or 99.95% of the total atomic mass.
  2. ^ A carat is 200 milligrams. By definition, carbon-12 has 0.012 kg per mole. The Avogadro constant defines 6 × 1023 atoms per mole.

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External links


1911 encyclopedia

Up to date as of January 14, 2010

From LoveToKnow 1911

ATOM (Gr. .c.royos, indivisible, from aprivative, and ,uvEiv, to cut), the term given in physical science to the ultimate indivisible particle of matter, and so by analogy to something minutely small in size.^ An ultimate particle of matter not necessarily indivisible; a molecule.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]
  • Definition of ATOM (Meaning of ATOM), a 4 Letter Word 19 January 2010 8:48 UTC www.hyperdictionary.com [Source type: Reference]

^ Physics (a) An ultimate indivisible particle of matter.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

^ B.C. the Greek philosophers Democritus and Leucippus proposed that matter was made up of tiny, indivisible particles they called atom, or in Greek "a-tomos".
  • WikiAnswers - Who discovered the atom 2 February 2010 13:34 UTC wiki.answers.com [Source type: General]

.If we examine such a substance as sugar we find that it can be broken up into fine grains, and these again into finer, the finest particles still appearing to be of the same nature as sugar.^ Each of these particles have about the same weight.

^ The important part is that these jumps cannot be broken down into smaller steps.
  • Bohr's Atom 2 February 2010 13:34 UTC www.colorado.edu [Source type: Original source]

^ Each element is made up of tiny indivisible particles called atoms (* actually, atoms are divisible; they can be broken up into smaller particles -- some of these smaller particles are discussed below) .
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

.The same is true in the case of a liquid such as water; it can be divided into drops and these again into smaller drops, or into the finest spray the particles of which are too small to be detected by our unaided vision.^ The same is true of when clauses in case statements.

^ Small particles suspended in liquid move spontaneously in a random fashion.
  • General Chemistry Online: Glossary: Atoms, elements, and ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Reference]

^ Atoms are much smaller than the wavelengths of light that human vision can detect, so atoms cannot be seen in any kind of optical microscope .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

.In fact, so far as the direct evidence of our senses tells us, matter appears to be indefinitely divisible.^ It is the impact of these on our sense organs that enables us to perceive.
  • Democritus (Stanford Encyclopedia of Philosophy) 2 February 2010 13:34 UTC plato.stanford.edu [Source type: FILTERED WITH BAYES]

^ Our work as librarians, repository managers, information technologists is NOT, though, as much a matter of educating users as it is educating ourselves, looking “outside the walls,” and beginning the difficult conversations that start moving us in the right direction.
  • Peter Keane's Miscellanea · Atom 2 February 2010 13:34 UTC blogs.law.harvard.edu [Source type: FILTERED WITH BAYES]

^ Tell us how we're doing: Please answer a few questions about your experience to help us improve our Help Center.
  • Atom 0.3 specification - Google Base Help 2 February 2010 13:34 UTC base.google.com [Source type: General]

.Moreover, small particles do not seem to exist in the water until it is broken up; so far as we can see, the material of the water is continuous not granular.^ Alpha rays rapidly dissipate their energy as they pass through materials, and are far less penetrating than beta particles and gamma rays .
  • General Chemistry Online: Glossary: Atoms, elements, and ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Reference]
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ Each element is made up of tiny indivisible particles called atoms (* actually, atoms are divisible; they can be broken up into smaller particles -- some of these smaller particles are discussed below) .
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

^ For example, water is made of two hydrogen atoms linked to an oxygen atom, hence its chemical formula, H 2 O. Atoms are themselves made up of even smaller particles.

.This conception of matter, as infinitely divisible and continuous, was taught by Anaxagoras more than four centuries before the Christian era, and in the philosophy of Aristotle the same ideas are found.^ The Christian Church continued to count years AUC for centuries after the fall of Rome.
  • Units: A 2 February 2010 13:34 UTC www.unc.edu [Source type: Reference]

^ It is on the doctrine of the illusive nature of matter, and the infinite divisibility of the atom, that the whole science of Occultism is built.

^ This research is supported by more than 200 epidemiological studies, which was the result of more than 2,500 laboratory studies that support the concept.
  • Stan Gardner, M.D. — Healthy Alternatives to Drugs and Surgery 2 February 2010 13:34 UTC www.stangardnermd.com [Source type: FILTERED WITH BAYES]

.But some phenomena are difficult to reconcile with pressed into less than one five-hundredth of a cubic foot, or, if allowed to expand, the air originally occupying the cubic foot can be made to fill, apparently uniformly, a space of a million cubic feet or more.^ Matter is made of either the atoms of one element or more than one element.
  • States of Matter Facts- Dialogue for Kids (Idaho Public Television) 2 February 2010 13:34 UTC idahoptv.org [Source type: FILTERED WITH BAYES]

^ More than anything, I just wanted to be able to provide at least one good photo for each parent to use in their Christmas cards and birth announcements.

^ The effective size of this aperture can be selected to allow passage of just one atom or the atoms originating from an area a few atoms wide.
  • Seeing and Catching Atoms: ORNL's Atom Probe Field Ion Microscope 2 February 2010 13:34 UTC www.ornl.gov [Source type: Academic]

.This enormous capacity for expansion and contraction is astonishing if we believe matter to be continuous, but if we imagine air to be made up of little particles separated by relatively large empty spaces the changes in volume are more easily conceivable.^ Most matter consists of an agglomeration of molecules, which can be separated relatively easily.
  • atom (matter) -- Britannica Online Encyclopedia 19 January 2010 8:48 UTC www.britannica.com [Source type: Academic]

^ A constituent particle of matter, or a molecule supposed to be made up of subordinate particles.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

^ That they were invisible because of their small size, were solid, were surronded by empty space (to explain movement and density changes), had an infinite number of shapes, and were eternal , because they were perfect.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

.Moreover, if we attribute such a structure to gases, we are led to attribute it to liquids and to solids also, since gases can be liquefied without any abrupt change, and many substances usually solid can be converted into gases by heating them.^ Without these forces, solids and liquids would act as gases.

^ Volatilize Volatilizing liquids converts them into gases.
  • Glossary 2 February 2010 13:34 UTC www.chem.wisc.edu [Source type: FILTERED WITH BAYES]

^ By definition, minerals have the following characteristics: 1) they are natural (not artificial) substances 2) they are solid 3) they form by inorganic processes 4) they have a specific chemical composition 5) they have a characteristic crystal structure .
  • Atoms 2 February 2010 13:34 UTC www.indiana.edu [Source type: FILTERED WITH BAYES]

.This conception of the grained structure of matter is very ancient; traces of it are to be found in Indian philosophy, perhaps twelve centuries before the Christian era, and the Greek philosophers Democritus and Epicurus, in the 3rd and 4th centuries B.C., taught it very definitely.^ One of the questions that ancient Greeks thinkers debated was the structure of matter.
  • Atom - body, used, chemical, energy, oxygen, parts, History, Modern models of the atom, Physical dimensions 2 February 2010 13:34 UTC www.scienceclarified.com [Source type: FILTERED WITH BAYES]

^ BC by the Greek philosophers Leucippus and Democritus and was adopted by the Roman Lucretius.
  • atom Facts, information, pictures | Encyclopedia.com articles about atom 19 January 2010 8:48 UTC www.encyclopedia.com [Source type: FILTERED WITH BAYES]

^ An ancient term of philosophical speculation (in Leucippus, Democritus), revived 1805 by British chemist Dalton.
  • Atoms | Definition of Atoms at Dictionary.com: 2 February 2010 13:34 UTC dictionary.reference.com [Source type: Reference]
  • Atom Definition | Definition of Atom at Dictionary.com 19 January 2010 8:48 UTC dictionary.reference.com [Source type: Reference]

.Their view was that "matter is not indefinitely divisible, but that all substances are formed of indivisible particles or atoms which are eternal and unchangeable, that the atoms are separated from one another by void, and that these atoms, by their combinations, form the matter we are conscious of."^ All forms of matter are composed of one or more elements.
  • CHEMISTRY I: ATOMS AND MOLECULES 2 February 2010 13:34 UTC www.emc.maricopa.edu [Source type: Academic]

^ He called these basic matter particles, atoms.
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

^ All matter is composed of extremely small particles called atoms.
  • All matter is made up of tiny particles called atoms 2 February 2010 13:34 UTC js082.k12.sd.us [Source type: Reference]

.The Roman poet Lucretius (De Rerum Natura) was an eloquent exponent of this theory, but throughout the middle ages, indeed until the 17th century, it was eclipsed by the prestige of Aristotle.^ This is the doctrine of atomacity, upheld by Epicurus , and enlarged on by Lucretius in his "De Rerum Natura".
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Little conceptual progress in atomic theory was made over the next two thousand years, in large part because Aristotle discredited it, and his views held sway through the Middle Ages.

^ During the Middle Ages (the Islamic Golden Age ), Islamic atomists develop atomic theories that represent a synthesis of both Greek and Indian atomism.
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

.In the time, however, of Boyle 1 and Newton, we again find an atomic theory of matter; Newton 2 regarded a gas as consisting of small separate particles which repelled one another, the tendency of a gas to expand being attributed to the supposed repulsion between the particles.^ Sometimes electrons are described as being small particles of matter.

^ For example, the symbol for uranium is U (atomic number 92); the isotopes of uranium with atomic weights 235 and 238 are indicated by 235 92 U and 238 92 U. Development of Atomic Theory Early Atomic Theory The atomic theory, which holds that matter is composed of tiny, indivisible particles in constant motion, was proposed in the 5th cent.
  • atom Facts, information, pictures | Encyclopedia.com articles about atom 19 January 2010 8:48 UTC www.encyclopedia.com [Source type: FILTERED WITH BAYES]

^ Tendency of an organism to suit its environment; one of the major points of Charles Darwin's theory of evolution by natural selection : organisms adapt to their environment.

.Let us consider some common phenomena in the light of these rival theories as to the nature of matter.^ Let's look at some other theories: the theory of evilution and the theory of universal gravitation (which claims that stars are affected by gravity; if so, why don't they fall to earth already?
  • Atom - Uncyclopedia, the content-free encyclopedia 2 February 2010 13:34 UTC uncyclopedia.wikia.com [Source type: Original source]

^ If you have some spare time, please take a look at these and test them and let me know of any problems.
  • Blogging Roller: Entries tagged [atom] 2 February 2010 13:34 UTC rollerweblogger.org [Source type: General]

^ Of the 92 naturally-occurring, four of these make up about 96% of all living matter.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

.When a few lumps of sugar are added to a glass of water and stirred, the sugar soon disappears and we are left with a uniform liquid resembling water, except that it is sweet.^ When solid sodium chloride is added to water (and briefly stirred) it dissolves to form a solution of sodium ions and chloride ions.

What has become of the sugar? Does it still exist ? .The atomist would say, "Yes, it is broken up into its atoms, and these are distributed throughout the spaces between the particles of water."^ As these particles have mass the atom should have a mass.
  • Atomic Structure Discovered 11 September 2009 3:41 UTC www.neoam.cc.ok.us [Source type: Original source]

^ These particles were called atoms .
  • Structure of the Atom (grades 6-8) 2 February 2010 13:34 UTC www.nyu.edu [Source type: FILTERED WITH BAYES]
  • Structure of the Atom (grades 6-8) 2 February 2010 13:34 UTC www.nyu.edu [Source type: FILTERED WITH BAYES]

^ Approximately 50 million atoms of solid matter lined up in a row would measure 1 cm (0.4 inch).
  • atom (matter) -- Britannica Online Encyclopedia 19 January 2010 8:48 UTC www.britannica.com [Source type: Academic]

.The rival philosopher, who believes water to be continuous and without spaces between its particles, has a greater difficulty in accounting for the disappearance of the sugar; he would probably say that the sugar, and the water also, had ceased to exist, and that a new continuous substance had been formed from them, but he could offer no picture of how this change had taken place.^ Kuzmich says having 10 billion atoms compressed into the same space would boost efficiency.
  • Physicists Succeed In Transferring Information Between Matter And Light 2 February 2010 13:34 UTC www.spacedaily.com [Source type: FILTERED WITH BAYES]

^ NO REPUBLISHING IN ANY FORM (including on other websites), in whole or in part, for any reason, without written permission.
  • Anatomy of the Atom (EnvironmentalChemistry.com) 2 February 2010 13:34 UTC environmentalchemistry.com [Source type: FILTERED WITH BAYES]
  • Periodic Table of Elements: Plutonium – Pu (EnvironmentalChemistry.com) 11 September 2009 3:41 UTC environmentalchemistry.com [Source type: Academic]
  • Periodic Table of Elements: Palladium – Pd (EnvironmentalChemistry.com) 11 September 2009 3:41 UTC environmentalchemistry.com [Source type: Academic]

^ Atomic energy first recorded 1906; atomic bomb first recorded 1914 in writings of H.G. Wells, who thought of it as a bomb "that would continue to explode indefinitely."
  • Atoms | Definition of Atoms at Dictionary.com: 2 February 2010 13:34 UTC dictionary.reference.com [Source type: Reference]
  • Atom Definition | Definition of Atom at Dictionary.com 19 January 2010 8:48 UTC dictionary.reference.com [Source type: Reference]

.Or consider a well-marked case of what we are in the habit of calling chemical combination. If 127 parts of iodine, which is an almost black solid, and loo parts of mercury, which is a white liquid metal, be intimately mixed by rubbing them together in a mortar, the two substances wholly disappear, and we obtain instead a brilliant red powder quite unlike the iodine or the mercury; almost the only property that is unchanged is the weight.^ Two or more atoms chemically combined.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

^ Alloying Mixing of metal with other substances (usually other metals) to modify its properties.
  • Chemistry Definitions A 2 February 2010 13:34 UTC home.nas.net [Source type: Reference]

^ This property of isomorphic crystals enabled experimenters to correct mistakes that might arise from a consideration of combining weights alone, and served as a guide to the correct atomic weights.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

The question again arises, what has become of the original substances? .The atomist has an easy answer; he says that the new body is made up by the juxtaposition of the atoms of iodine and mercury, which still exist in the red powder.^ Your body is made up of many, many individual atoms.

^ Matter is made up of indivisible atoms.

^ All matter is made up of atoms.
  • Background: Atoms and Light Energy 2 February 2010 13:34 UTC imagine.gsfc.nasa.gov [Source type: FILTERED WITH BAYES]

.His opponent would be disposed to say that the iodine and the mercury ceased to exist when the red powder was formed, that they were components but not constituents of it.^ But if anyone could break that single atom into smaller pieces, the gold atom would cease to exist.

^ If there are more electrons, they must have the next amount of energy (they have to buy 5¢ seats), or as a chemist would say, they’re filling the second energy shell.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

^ The atoms unite to form molecules and cannot exist except as constituents of molecules.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

The fact that the two components can be recovered from the compound by destroying it does not decide the question. .It is remarkable that pure chemistry, even to-day, has no very conclusive arguments for the settlement of this controversy; but the sister science of physics is steadily accumulating evidence in favour of the atomic conception.^ To put this into scientific terms for all the science minded, Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

^ Related Searches: electron , quantum , radiation , molecule , atomic , nuclear , chemistry , physics , science , nerd , geek , Geeks / Technology , funny , Humor You've come to the right place for atom gifts.
  • Atom Gifts, T-shirts, Stickers and more - CafePress 2 February 2010 13:34 UTC shop.cafepress.com [Source type: General]

^ The pursuit of the structure of the atom has married many areas of chemistry and physics in perhaps one of the greatest contributions of modern science.
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

.Until the time of John Dalton, the atomic conception remained purely qualitative, and until then it does not appear to have 1 Robert Boyle, The Sceptical Chymist (1661); The Usefulness of Natural Philosophy (1663).^ The idea of the atom was first devised by Democritus in 530 B.C. In 1808, an English school teacher and scientist named John Dalton proposed the modern atomic theory.
  • HowStuffWorks "What is an Atom?" 2 February 2010 13:34 UTC science.howstuffworks.com [Source type: FILTERED WITH BAYES]
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ Understanding of atoms didn’t progress much beyond Demokritos’ theory until the English chemist John Dalton (1766 - 1844) started to look at it in the 1800s.
  • BBC - GCSE Bitesize: Early ideas about atoms 2 February 2010 13:34 UTC www.bbc.co.uk [Source type: FILTERED WITH BAYES]

^ Chronos is the sort of theme oriented villain found more often in John Broome's Flash stories: everything he does is related to time.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

.Sir Isaac Newton, Principia, bk.^ Sir Isaac Newton's Second Law of Motion states: the magnitude of a force=mass*acceleration.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

ii. prop. 23.
advanced chemistry or to have found further confirmation in the facts of chemistry. .Dalton (1803) gave the atomic theory a quantitative form, and showed that, by means of it, a vast number of the facts of chemistry could be predicted or explained.^ Dalton's atomic theory formed the groundwork of chemistry at that time.
  • HowStuffWorks "What is an Atom?" 2 February 2010 13:34 UTC science.howstuffworks.com [Source type: FILTERED WITH BAYES]
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ Learning check for Dalton's atomic theory .
  • General Chemistry Online: Companion Notes: Atoms & ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Academic]

^ State the premises of Dalton's atomic theory .
  • General Chemistry Online: Companion Notes: Atoms & ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Academic]

.In fact, he did so much to make the atomic theory of matter probable that he is popularly regarded as its originator.^ Atomic Theory Study Guide - Important Facts Atoms and Atomic Theory - Study Guide Matter Structure Everything you ever needed to know about pH: Part I determining the acidity...
  • Basic Model of the Atom - Introduction to Atoms 2 February 2010 13:34 UTC chemistry.about.com [Source type: FILTERED WITH BAYES]

^ Valence Bond Theory Classification of Matter Atomic Orbitals Significant Figures Measurements (32 knoles y recopilaciones) Traducciones del knol .
  • Atoms - un knol de Glenn Lo 2 February 2010 13:34 UTC knol.google.com [Source type: Reference]

^ Centuries later, in 1803, the English chemist John Dalton, guided by the experimental fact that chemical elements cannot be decomposed chemically, was led to formulate his atomic theory.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

.Dalton lived in a period marked by great advances in experimental chemistry.^ Experimental foundation of atomic chemistry - - Atomic weights and the periodic tab...
  • atom (matter) -- Britannica Online Encyclopedia 19 January 2010 8:48 UTC www.britannica.com [Source type: Academic]

.Rather before the commencement of the 19th century the work of Lavoisier had rendered it very probable that chemical changes are not accompanied by any change in weight, and this principle of the conservation of matter was becoming universally accepted; chemists were also acquiring considerable skill in chemical analysis, that is, in the determination of the nature and relative amounts of the elements contained in compounds.^ All living and non-living compounds of the universe are composed of chemical elements.

^ This determines the chemical properties of the element.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

^ Isotopes What determines the chemical characteristics of elements?

.But Sir H. E. Roscoe and A. Harden, New View of the Atomic Theory (1896), have shown, from a study of Dalton's manuscript notes, that we do not owe his atomic theory to such experiments.^ Dalton's Atomic Theory (1808): This was the first atomic theory that was based on experiments.
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

^ Notes More about Dalton's atomic theory .
  • General Chemistry Online: Companion Notes: Atoms & ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Academic]

^ Learning check for Dalton's atomic theory .
  • General Chemistry Online: Companion Notes: Atoms & ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Academic]

If their view is correct, the theory appears to be a remarkable example of deductive reasoning. .Dalton, who was a mathematical physicist even more than a chemist, had given much thought to the study of gases.^ Given that blue light is more energetic than red, other things being equal, which electron jump in the figure will produce blue light?

^ License: GPL A Blog and feed aggregation solution specifically designed for people who need to scan through much more information than others and are subscribing to hundreds of information feeds - blogs, data .
  • i use this osx software: keyword: atom 19 January 2010 8:48 UTC osx.iusethis.com [Source type: General]

^ An example of this notion of reality is given by the famous Cornell physicist N. David Mermin who says "We now know that moon is demonstrably not there when nobody looks."

.Following Newton, he believed a gas to be made up of particles or atoms, From Dalton's Hydrogen Gas.^ Each atom is made of subatomic particles.

^ Matter is made up of indivisible atoms.

^ This made the whole Newton/Dalton picture difficult to believe.

Nitrous Gas. Carbonic Acid Gas.
separated from one another by considerable paces. .Certain difficulties that he met with in his speculations led him to the conclusion that the particles of any one kind of gas, though all of them alike, must differ from those of another gas both in size and weight. He thus arrived at the conception of a definite atomic weight peculiar to the particles of each gas, and he thought that he could determine these atomic weights, in terms of one of them, by means of the quantitative analysis of compounds.^ Understand the concept of atomic weight .
  • General Chemistry Online: Companion Notes: Atoms & ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Academic]

^ Between these all the other atomic weights lie.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ The range of the atomic weights is a narrow one.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

.The conclusion that each element had a definite atomic weight, peculiar to it, was the new idea that made his speculations fruitful, because it allowed of quantitative deduction and verification.^ For the atomic weight of individual elements, see Element .

^ If the elements are written down in the order of their atomic weights, beginning with the lightest and ending with the heaviest, it will be found that the position of an element in the series will indicate pretty clearly its properties.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ In 1808, a book published by John Dalton , " A New System of Chemical Philosophy " , revealed experimental conclusion s that all atoms of an element had the exact same size and weight, and that all molecules were formed by simple ratios of atoms.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

.He drew simple diagrams, three of which, taken from Dalton's New System of Chemical Philosophy, part ii.^ Dalton wrote A New System of Chemical Philosophy , from which the following quotes are taken: .

^ In 1808, a book published by John Dalton , " A New System of Chemical Philosophy " , revealed experimental conclusion s that all atoms of an element had the exact same size and weight, and that all molecules were formed by simple ratios of atoms.
  • atom@Everything2.com 2 February 2010 13:34 UTC www.everything2.com [Source type: FILTERED WITH BAYES]

^ In 1808, he published A New System of Chemical Philosophy , in which his atomic theory was discussed in greater detail.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.(r 810), are reproduced here, in which gases are represented as composed of atoms.^ All this takes for granted the fact that the particles of different gases, whether composed of single atoms or of combinations of atoms, are indeed equally spaced apart.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Here is REMARK  10 from the 1acp PDB entry: Pseudo-atoms designated as Q are dimensionless reference points representing a group of hydrogen atoms.
  • PDB ATOM format 2 February 2010 13:34 UTC bmerc-www.bu.edu [Source type: FILTERED WITH BAYES]

.Knowing that the gas which he called "nitrous gas" was composed of oxygen and nitrogen, and believing it to be the simplest compound of these two elements, he naturally represented its atom as formed of an atom of oxygen and an atom of nitrogen in juxtaposition.^ When an element has atoms that differ in the number of neutrons, these atoms are called different isotopes of the element.
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

^ Composed of one or two letters that have been assigned to     represent that particular element.

^ These elements are diatomic molecules in their natural form.

.When two elements form more than one compound, as is the case with oxygen and carbon, he assigned to the compound which he thought the more complex an atom made up of two atoms of the one element and one atom of the other; the diagram for carbonic acid illustrates this, and an extension of the same plan enabled him to represent any compound, however complex its structure.^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ An Atom feed is made up of standardized elements.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ Composed of one or two letters that have been assigned to     represent that particular element.

.The table here given contains some of Dalton's diagrams of atoms.^ It had been known for some time that the light given out when atoms were heated always had specific amounts of energy, but no one had been able to explain this.

^ Here are some of the people who helped figure out the atom: mid-1600s, Boyle: all matter is made of atoms.
  • Atoms 2 February 2010 13:34 UTC www.dmturner.org [Source type: Original source]

^ Bohr said, "Here's some rules that seem impossible, but they describe the way atoms operate, so let's pretend they're correct and use them."
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

.They are not all considered to be correct at the present time; for example, we now think that the ultimate particle of water is made up of two atoms of hydrogen and one of oxygen, and that that of ammonia contains three atoms of hydrogen to one of nitrogen.^ Each atom is made of subatomic particles.

^ Unfortunately only two of the three assumptions that were made for LiI are correct.

^ An atom contains several kinds of particles.

.But these differences between Dalton's views and our present ones do not impair the accuracy of the arguments which follow.^ An important difference between Berzelius's table and Dalton's was that Berzelius's values were not, generally, whole numbers.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Some of the differences between chemical compounds and mixtures of elements are illustrated by the following example using raisin bran and "Crispix.".

^ Understand the difference between Bohr Rutherford and the Quantum Mechanic View.
  • Curriculum Unit - Atomic Structure/ Molecular Architecture 11 September 2009 3:41 UTC educ.queensu.ca [Source type: FILTERED WITH BAYES]

this view; for example, a cubic foot of air can be corn 0 hydrogen. 0 oxygen. O nitrogen.
carbon.
water.
ammonia. ethylene.
carbon monoxide. carbon dioxide. nitric oxide (nitrous gas). nitrous oxide. nitrogen peroxide.
.00 O (DOG The diagrams show that Dalton formed a very definite conception of the nature of chemical combination; it was the union of a small number of atoms of one kind with a small number of another kind to form a compound atom, or as we now say a "molecule," this identical process being repeated millions of times to form a perceptible amount of a compound.^ But now I’m not the only one saying it.

^ When atoms combine with each other they form chemical bonds between the atoms.

^ Two or more atoms chemically combined.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

.The conceptions of "element," "compound" and "mixture" became more precise than they had been hitherto; in an element all the atoms are alike, in a compound all the molecules are alike, in a mixture there are different kinds of molecules.^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ There are only a few more than one hundred elements.
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

^ MUST NOT contain more than one atom:icon element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.If we accept the hypothesis that each kind of atom has a specific and invariable weight, we can, with the aid of the above theory, make most important inferences concerning the proportions by weight in which substances combine to form compounds.^ Elements combine to form compound substances of various numbers of atoms in the molecule.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Chemical compounds are formed when atoms combine with each other.
  • learnchem.net: Atoms Tutorial 2 February 2010 13:34 UTC learnchem.net [Source type: Original source]

^ Atoms combine with each other to form molecules.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

.These inferences are often summarized as the laws of constant, multiple and reciprocal proportions. The law of constant proportions asserts that when two elements unite to form a compound the weights that combine are in an Law of invariable ratio, a ratio that is characteristic of that compound. Thus if Dalton's diagram for the molecule, propor- or compound atom, of water be correct, it follows that in all samples of water the total number of the hydrogen atoms is equal to that of the oxygen atoms; consequently, the ratio of the weight of oxygen to that of hydrogen in water is the same as the ratio of the weights of an oxygen and a hydrogen atom, and this is invariable. Different samples of water cannot therefore differ ever so little in percentage composition, and the same must be true for every compound as distinguished from a mixture.^ Each atom has an equal number of protons and electrons.

^ Elements combine to form chemical compounds that are often divided into two categories.

^ The hydrogen ion (H + ) attaches to another water molecule forming a hydronium ion (H 3 O + ).

.Apart from the atomic theory there is no obvious reason why this should be so.^ The physical indivisibility of the atoms seems to be independent of the argument for indivisible magnitudes, since the solidity of atoms—the fact that there is no void within them—is said to be the reason why they cannot be split.
  • Democritus (Stanford Encyclopedia of Philosophy) 2 February 2010 13:34 UTC plato.stanford.edu [Source type: FILTERED WITH BAYES]

^ However, there is one very good reason in particular why scientists should want to change all that.
  • Under Observation -- Restless Atoms Cause Materials to Age 2 February 2010 13:34 UTC www.physorg.com [Source type: FILTERED WITH BAYES]

^ Clients should start at the beginning of the feed, and continue requesting pages of data until there are no more.
  • InfoQ: AtomServer – The Power of Publishing for Data Distribution 2 February 2010 13:34 UTC www.infoq.com [Source type: FILTERED WITH BAYES]

.We give the name bread to a substance containing variable proportions of flour and water.^ Once the atomic theory was accepted, one could picture substances as composed of molecules containing a fixed number of atoms of various elements.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ At any instant in time, a large proportion of water molecules are bonded to nearby water molecules, giving water a cohesive property.

^ The same process gives the proportion of oxygen in water as 16/18.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

Similarly the substance we call wine is undeniably variable in composition. .Why should not the substance we call water also vary more or less?^ For most substances, the solid form is more dense than the liquid form and would sink to the bottom of any mixture of the two, but for water, the solid (ice) is less dense.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

^ A given amount of heat energy will change the temperature of water less than it will change the temperature of most other kinds of substances.

^ They concluded that the variations in mass result, more or less, from the number of neutrons in the nucleus of the atom.
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

.The Aristotelian would find no difficulty in such a variability; it is only the disciple of Dalton to whom it seems impossible.^ In the 1800's an English chemist, John Dalton performed experiments with various chemicals that showed that matter, indeed, seem to consist of elementary lumpy particles (atoms).
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

^ After fending him off would ask himself the same questions “Why Am I gold?” and “How can I get home?” for throughout the series finding it impossible to leave.
  • Captain Atom (comic book character) - comicvine.com 2 February 2010 13:34 UTC www.comicvine.com [Source type: FILTERED WITH BAYES]

^ If only someone would create such a standard!

It is evident that we have in this law a definite prediction that can be tested by experiment.
.The law of multiple proportions asserts that if two elements form more than' one compound, then the weights of the one element Law of which are found combined with unit weight of the other multiple in the different compounds, must be in the ratio of two propor or more whole numbers. If we compare Dalton's diagrams of the two oxides of carbon or of the three oxides of nitrogen that are given in the preceding table, we at once see the necessity of this law; for the more complex molecule has to be formed from the simpler one by the addition of one or more whole atoms.^ MUST NOT contain more than one atom:summary element.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ An important difference between Berzelius's table and Dalton's was that Berzelius's values were not, generally, whole numbers.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Person constructs MAY contain an atom:uri element, but MUST NOT contain more than one.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.In the oxides of carbon the same weight of carbon must be combined with weights of oxygen that are as 2, and in the oxides of nitrogen a fixed weight of nitrogen must be in union with weights of oxygen that are as 1: 2: 2, which are the same ratios as 2: 4: r.^ In one combination, these gases formed dinitrogen trioxide (N 2 O 3 ), but when he repeated the combination with double the amount of oxygen (a ratio of 1:2), they instead formed nitrogen dioxide (NO 2 ).
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ The acids form when sulfur dioxide and nitrogen oxides released during the combustion of fossil fuels combine with water and oxygen in the atmosphere.

^ MUST NOT contain more than one atom:link element with a rel attribute value of "alternate" that has the same combination of type and hreflang attribute values.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.This law has been abundantly verified by experiment; for example, five oxides of nitrogen are known, and independent analyses show that, if we consider the same weight of nitrogen in every case, the weights of oxygen combined with it are to one another as i: 2: 3: 4: 5. The discovery of this law is due to Dalton; it is a direct deduction from his atomic theory.^ Another unit equivalent to an atomic mass unit is the Dalton; one Dalton is defined as 1 u.
  • Atoms - un knol de Glenn Lo 2 February 2010 13:34 UTC knol.google.com [Source type: Reference]

^ One of the strongest arguments for Dalton's atomic theory of chemistry was the Law of Multiple Proportions.

^ The range of the atomic weights is a narrow one.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

.Here again, apart from this theory, there is no obvious reason why the composition of different substances should be related in so simple a way.^ There is no way to separate the "elements" without breaking the bonds that hold them together.

^ The physical indivisibility of the atoms seems to be independent of the argument for indivisible magnitudes, since the solidity of atoms—the fact that there is no void within them—is said to be the reason why they cannot be split.
  • Democritus (Stanford Encyclopedia of Philosophy) 2 February 2010 13:34 UTC plato.stanford.edu [Source type: FILTERED WITH BAYES]

^ Note that the number of electrons associated with the oxygen atom remains the same, there is no loss or gain - it only oxidizes different atoms in the process.

.As Dalton said, "The doctrine of definite proportions appears mysterious unless we adopt the atomic hypothesis."^ When Dalton put forward his new version of the atomic theory based on the laws of definite proportions and of multiple proportion, in 1803, he acknowledged the debt to Democritus by keeping the term "atom" for the small particles that made up matter.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

"It appears like the mystical ratios of Kepler which Newton so happily elucidated." .The chemists of Dalton's time were not unanimous in accepting these laws; indeed C. L. Berthollet (Essai de statique chimique, 1803) expressly controverted them.^ Centuries later, in 1803, the English chemist John Dalton, guided by the experimental fact that chemical elements cannot be decomposed chemically, was led to formulate his atomic theory.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

^ In the 1800's an English chemist, John Dalton performed experiments with various chemicals that showed that matter, indeed, seem to consist of elementary lumpy particles (atoms).
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

.He maintained that, under varying conditions, two substances could combine in an indefinitely large number of different ratios, that there could in fact be a continuous variation in the combining ratio.^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ Professor Thomson shown that such particles, under the conditions outlined above, arrange themselves into groups of various arrangement, the latter depending on their number.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Apparent Density The ratio of mass to volume of a finely powdered material, under stated conditions, which is always less than true density.

.This view is clearly inconsistent with the atomic theory, which requires that when the combining ratio of two substances changes it should do so, per saltum, to quite another value.^ The grain boundary is clearly seen in this micrograph because of the presence of a series of bright dots and the abrupt disruption of the concentric rings at the boundary where the orientation of the two crystalline grains changes.
  • Seeing and Catching Atoms: ORNL's Atom Probe Field Ion Microscope 2 February 2010 13:34 UTC www.ornl.gov [Source type: Academic]

^ Molecule : A combination of two or more atoms bound together electrically; the smallest part of a compound that has the properties of that substances.
  • Glossary of Terms for UNH ESPG 2 February 2010 13:34 UTC www-ssg.sr.unh.edu [Source type: FILTERED WITH BAYES]

^ If the two gases combine, they rearrange themselves to form hydrogen-chlorine, the atomic combination making up the hydrogen chloride molecule.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.The law of reciprocal proportions, or, as it might well be named, the law of equivalence, cannot be adequately enunciated in a few words.^ In other words, if matter consisted of atoms, then the law of definite proportions followed as a natural consequence.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ His second law of electrolysis stated: The weight of metal liberated by a given quantity of electricity is proportional to the equivalent weight of the metal.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

The following gives a partial statement of it. .Law of If we know the weights a and b of two elements that are reciprocal found in union with unit weight of a third element, then proporwe can predict the composition of the compounds which the first two elements can form with each other; either the weights a and b will combine exactly, or if not, these weights must be multiplied by integers to obtain the composition of a compound.^ Elements combine to form chemical compounds that are often divided into two categories.

^ Because most elements tend to combine with others, few elements are found in their pure form.
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

^ These are gases which combine to form a third gas, hydrogen chloride.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.To see how this law follows from Dalton's theory let us consider his diagrams for the molecules of water, ethylene and the oxides of carbon.^ Atomic theory matter: solid, liquid, gas, plasma, ideal gas law, phase diagram .
  • Atomic structures, atoms and molecules 2 February 2010 13:34 UTC www.educypedia.be [Source type: Academic]

^ Atoms: By Takalah Topics Covered Law of Multiple Proportions Dalton's Atomic Theory Intro to Atomic Structure Molecules and Ions Compound Naming This section introduces some basic concepts of chemistry.
  • learnchem.net: Atoms Tutorial 2 February 2010 13:34 UTC learnchem.net [Source type: Original source]

^ These records are used for water molecules and atoms presented in HET groups (see http://deposit.pdb.org/public-component-erf.cif).
  • wwPDB Format version 2.3: Coordinate Section 2 February 2010 13:34 UTC www.wwpdb.org [Source type: Reference]

.In water and in ethylene experiment shows that 8 parts by weight of oxygen and 6 parts of carbon, respectively, are in union with one part of hydrogen; also, if the diagrams are correct, these numbers must be in the ratio of the atomic weights of oxygen and carbon.^ Measurement shows that 3 parts of carbon (by weight) will combine with 8 parts of oxygen to form carbon dioxide.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ The ratio spoken of above of 1:8, is therefore the ratio of two atoms of hydrogen to one of oxygen.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Number of these gives atomic number.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

.We can therefore predict that all oxides of carbon will have compositions represented by the ratio of 8m parts of oxygen to 6n parts of carbon, where m and n are whole numbers.^ However, the -hcb option to filter-pdb-atoms.pl violates this rule by generating all its hallucinated beta carbons with serial number 0.
  • PDB ATOM format 2 February 2010 13:34 UTC bmerc-www.bu.edu [Source type: FILTERED WITH BAYES]

^ The preparation was always 5.3 parts of copper to 4 of oxygen to 1 of carbon.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Because the charge to mass ratio was the same for any substance, the electrons were a basic part of all atoms .
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

This prediction is verified by the result of analysis. .Similarly, if we know by experiment the composition of water and of ammonia, we can predict the probable composition of the oxides of nitrogen.^ The acids form when sulfur dioxide and nitrogen oxides released during the combustion of fossil fuels combine with water and oxygen in the atmosphere.

.Experiment shows that, in water and ammonia, we have, respectively, 8 parts of oxygen and 4.67 parts of nitrogen in union with one part of hydrogen; we can therefore infer that the oxides of nitrogen will all have the composition of 8m parts of oxygen to 4.67n parts of nitrogen.^ The ratio spoken of above of 1:8, is therefore the ratio of two atoms of hydrogen to one of oxygen.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ For instance, 1 part (by weight) of hydrogen combined with 8 parts of oxygen to form water.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Did water have one oxygen with one hydrogen or one oxygen with two hydrogens?
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

.Experiment alone can tell us the values of m and n; all that the theory tells us is that they are whole numbers.^ All dates specify a moment (00:00) of a single day; they MUST NOT be taken as periods of a day or more, such as “the whole of July 2001″ or “the whole of 2000″.” .
  • Atom 0.2 snapshot [dive into mark] 2 February 2010 13:34 UTC diveintomark.org [Source type: General]

^ An important difference between Berzelius's table and Dalton's was that Berzelius's values were not, generally, whole numbers.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Yes, Irwin Moon is back telling us all about atomic energy and the atom bomb.
  • Internet Archive: Free Download: Living with the Atom 19 January 2010 8:48 UTC www.archive.org [Source type: FILTERED WITH BAYES]

.In this particular case, n turns out to be 3, and m has in succession the values I, 2, 3, 4, 5. It is evident that these laws all follow from the idea that a compound molecule can only alter through the addition or subtraction of one or more complete atoms, together with the idea that all the molecules in a pure substance are alike.^ It turns out that each element is made of only one kind of atom.
  • Atoms 2 February 2010 13:34 UTC www.dmturner.org [Source type: Original source]

^ This "atom" idea is flawed for these reasons: .
  • Atom - Uncyclopedia, the content-free encyclopedia 2 February 2010 13:34 UTC uncyclopedia.wikia.com [Source type: Original source]

^ Active only when the molecules are close together.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

.Fortunately, the compounds at first examined by the chemists engaged in verifying these laws were comparatively simple, so that the whole numbers referred to above were small.^ If any number of particles be taken they will show groupings, characteristic of the number, and subject to periodical reappearance of groupings is exactly comparable to the phenomena of the periodic law.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ The best evidence for his theory was the experimentally verified law of simple multiple proportions , which gives a relation between the weights of two elements that combine to form different compounds.
  • atom Facts, information, pictures | Encyclopedia.com articles about atom 19 January 2010 8:48 UTC www.encyclopedia.com [Source type: FILTERED WITH BAYES]

.The astonishing variety of ratios in which carbon and hydrogen combine was not at first realized.^ Avogadro was working with gases (nitrogen, hydrogen, oxygen, chlorine) and noticed that when temperature and pressure was the same, these gases combined in definite volume ratios.
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ Meanwhile in Paris, Joseph Louis Gay-Lussac investigated carefully the ratio of the volume of hydrogen gas that combined with a given volume of oxygen gas to form water.

^ Note that the second ratio is exactly twice the first, because there are exactly twice as many oxygens in CO 2 per carbon as there are in CO. mass number.
  • General Chemistry Online: Glossary: Atoms, elements, and ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Reference]

.Otherwise Berthollet's position would have been a much stronger one, and the atomic theory might have had to wait a long while for acceptance.^ That is, for every positive point along one wave, the second wave would have a negative counterpart of the same magnitude.
  • Glossary 2 February 2010 13:34 UTC www.chem.wisc.edu [Source type: FILTERED WITH BAYES]

^ They knew that the force which holds the protons together must occur much stronger than the electromagnetic force and that the force must act over very small distances (otherwise they would have noticed this force in interactions between the nucleus and the outer electrons).
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

^ Once the atomic theory was accepted, one could picture substances as composed of molecules containing a fixed number of atoms of various elements.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.Even at the present time, it would be too much to say that all the complex organic substances have been proved by analysis to obey these laws; all we can assert is that their composition and properties can be satisfactorily explained on the assumption that they do so.^ At present time Intel seems to be hinting that Diamondville will also carry the “Atom” branding but they’re vague on the specifics.
  • Intel christens Silverthorne as "Atom" | George Ou | ZDNet.com 2 February 2010 13:34 UTC blogs.zdnet.com [Source type: General]

^ Not that we are entitled to affirm that these substances we consider as simple may not be compounded of two, or even of a greater number of principles; but since these principles cannot be separated, or rather since we have not hitherto discovered the means of separating them, they act with regard to us as simple substances, and we ought never to suppose them compounded until experiment and observation have proved them to be so.

^ Although electrons are present in all atoms, and therefore in all normal substances, the outer electrons in conductive substances are freer to leave the parent atoms than the electrons of insulating substances.

.The above statement does not by any means exhaust the possible predictions that can be made from the atomic theory, but it shows how to test the theory.^ How is Bohr s atomic theory similar to the modern quantum mechanical model of the atom?
  • Curriculum Unit - Atomic Structure/ Molecular Architecture 11 September 2009 3:41 UTC educ.queensu.ca [Source type: FILTERED WITH BAYES]

^ The atomic theory, by the way, was a death blow (if any were needed) to belief in the possibility of transmutation of alchemical terms.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ The disagreement showed up in connection with water, in particular, even before Dalton had advanced his atomic theory.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.If chemical compounds can be proved by experiment to obey these laws, then the atomic theory acquires a high degree of probability; if they are contradicted by experiment then the atomic theory must be abandoned, or very much modified.^ Not that we are entitled to affirm that these substances we consider as simple may not be compounded of two, or even of a greater number of principles; but since these principles cannot be separated, or rather since we have not hitherto discovered the means of separating them, they act with regard to us as simple substances, and we ought never to suppose them compounded until experiment and observation have proved them to be so.

^ Atomic theory matter: solid, liquid, gas, plasma, ideal gas law, phase diagram .
  • Atomic structures, atoms and molecules 2 February 2010 13:34 UTC www.educypedia.be [Source type: Academic]

^ To put this into scientific terms for all the science minded, Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

.Dalton himself made many analyses with the purpose of establishing his views, but his skill as an analyst was not very great.^ He, next to Dalton himself, was chiefly responsible for the establishment of the atomic theory.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ It was not until the very end of the nineteenth century that this view was established and the "atoms of electricity" were located.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.It is in the work of the great Swedish chemist J. J. Berzelius, and somewhat later, in the experiments of the Belgian chemist J. S. Stas, that we find the most brilliant and vigorous verification of these laws, and therefore of the atomic theory.^ In the 1860's, for instance, the Belgian chemist Jean Servais Stas (1813-1891) determined atomic weights more accurately than Berzelius had done.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Although the Bohr model adequately explained how atomic spectra worked, there were several problems that bothered physicists and chemists: .
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ One by one these elements have been discovered, so that Mendeléeff's Law predicted the existence of elements later to be discovered.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

.We shall now give an outline of the experimental evidence for the truth of these laws.^ This gives the outlines of an explanation of the periodic law.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ The best evidence for his theory was the experimentally verified law of simple multiple proportions , which gives a relation between the weights of two elements that combine to form different compounds.
  • atom Facts, information, pictures | Encyclopedia.com articles about atom 19 January 2010 8:48 UTC www.encyclopedia.com [Source type: FILTERED WITH BAYES]

.The law of the conservation of matter, an important element in the atomic theory, has been roughly verified by innumerable analyses, in which, a given weight of a substance having been taken, each ingredient in it is isolated and its weight separately determined; the total weight of the ingredients is always found to be very nearly equal to the weight of the original substance.^ For the atomic weight of individual elements, see Element .

^ The corpucular theory also accounts for the variation of the elements in atomic weight.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ By running many hundreds of analyses, he advanced so many examples of the law of definite proportions that the world of chemistry could no longer doubt its validity and had to accept, more or less willingly, the atomic theory which had grown directly out of the law of definite proportions.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.But on account of experimental errors in weighing and measuring, and through loss of material in the transfer of substances from one vessel to another, such analyses are rarely trustworthy to more than one part in about Soo; so that small changes in weight consequent on the chemical change could not with certainty be proved or disproved.^ A change in the behavior of one part of a molecule caused by a change in another part of the molecule.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ A property that can be measured without changing the chemical composition of a substance.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

^ An expression of a fundamental change in the chemical substances.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

A few experimenters have carried the verification much further. .Stas, in his syntheses of silver iodide, weighed the silver and the iodine separately, and after converting them into the compound he weighed this also.^ The process of converting nitrogen from the atmosphere into usable nitrogen compounds is called nitrogen "fixing".

.In each of a number of experiments he found that the weight of the silver iodide did not differ by one twenty-thousandth of the whole from the sum of the weights of the silver and the iodine used.^ The various atoms had different weights because they were made up of different numbers of hydrogen atoms in conglomeration.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ One part of a level, each of which can hold different numbers of electrons.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

^ The term is often incorrectly used to refer to the whole of Indian cinema, but it is actually only one part a much bigger Indian film industry.
  • Australian Teachers of Media (Victoria) 2 February 2010 13:34 UTC atomvic.org [Source type: General]

.His analyses of another compound, silver iodate, confirm the law to one part in 78,000. In E. W. Morley's experiments on the synthesis of water the hydrogen, the oxygen and the water that had been formed were separately determined; taking the mean of his results, the sum of the weights of the ingredients is not found to differ from the weight of the product by one part in 10,000. It is evident that if our experiments are solely directed to the verification of this law, they should, if possible; be carried out in a hermetically closed vessel, the vessel and its contents being weighed before and after the chemical change.^ A change in the behavior of one part of a molecule caused by a change in another part of the molecule.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ He obtained only hydrogen and oxygen from the water.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Water is an example of a compound substance, or chemical compound.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

.The extremely careful experiments of this kind, by H. Landolt and others, made it at first appear that the change in weight, if there is any, consequent on a chemical change can rarely exceed one-millionth of the weight of the reacting substances, and that it must often be much less.^ An expression of a fundamental change in the chemical substances.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

^ They react readily with other substances.

^ The nucleus occupies less than one thousand million millionth (10 ) of the atomic volume, but contains almost all of the atom's mass.
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

.The small discrepancies found are so easily accounted for by attributing them to experimental errors that, until recently, every chemist would have regarded the law as sufficiently verified.^ Other chemists verified the law of definite proportions, and it became a cornerstone of chemistry.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ This formula was found to be correct within the limits of experimental error in measuring the quantities on the right.

^ In that year, too, his law of multiple proportions was verified by the investigations of another English chemist, William Hyde Wollaston (1766-1828).
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.Landolt's subsequent experiments showed, what was already noticed in the earlier ones, that these minute changes in weight are nearly always losses, the products weigh less than the components, while if they had been purely experimental errors, due to weighing, they might have been expected to be as frequently gains as losses.^ Alpha rays rapidly dissipate their energy as they pass through materials, and are far less penetrating than beta particles and gamma rays .
  • General Chemistry Online: Glossary: Atoms, elements, and ions 2 February 2010 13:34 UTC antoine.frostburg.edu [Source type: Reference]
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ In one combination, these gases formed dinitrogen trioxide (N 2 O 3 ), but when he repeated the combination with double the amount of oxygen (a ratio of 1:2), they instead formed nitrogen dioxide (NO 2 ).
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ The nucleus occupies less than one thousand million millionth (10 ) of the atomic volume, but contains almost all of the atom's mass.
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

.Landolt was disposed to attribute these losses in weight to the containing vessel, which was of glass or quartz, not being absolutely impervious, but in 1908 he showed that, by making allowance for the moisture adsorbed on the vessel, the errors were both positive and negative, and were less than one in ten million.^ The nucleus occupies less than one thousand million millionth (10 ) of the atomic volume, but contains almost all of the atom's mass.
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

^ MUST NOT contain more than one atom:summary element.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Atom Entry elements in Collection Documents SHOULD contain one app:edited element, and MUST NOT contain more than one.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

.He concluded that no change of weight can be detected. Modern researches (see Radioactivity) on the complex nature of the atom have a little shaken the belief in the absolute permanence of matter.^ The ancient Greek philosophers Leucippus and Democritus believed that atoms existed, but they had no idea as to their nature.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

^ This means that changes in the nucleus of radioactive atoms cause particles and energy to be given off.

^ It seemed very natural to try to picture such molecules by drawing the correct number of little circles, each type of atom represented by a specific type of circle.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.But it seems pretty clear that if there is any change in weight consequent on chemical change, it is too minute to be of im- portance to the chemist, though the methods of modern physics may settle the question.^ Shown here is a simplified representation of an atom : the smallest division of matter that may be isolated through physical or chemical methods.

^ Although it is not clear from Plutarch's report how (or if) Democritus solved the problem, it does seem that he was conscious of questions about the relationship between atomism as a physical theory and the nature of mathematical objects.
  • Democritus (Stanford Encyclopedia of Philosophy) 2 February 2010 13:34 UTC plato.stanford.edu [Source type: FILTERED WITH BAYES]

^ Instead, there was such a thing as an equivalent weight ; a fixed weight of one chemical reacted with a fixed weight of another chemical.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

(See Element.) .The law of constant proportions is easily verified to a moderate degree of accuracy by such experiments as the following.^ Other chemists verified the law of definite proportions, and it became a cornerstone of chemistry.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ In other words, if matter consisted of atoms, then the law of definite proportions followed as a natural consequence.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ In that year, too, his law of multiple proportions was verified by the investigations of another English chemist, William Hyde Wollaston (1766-1828).
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

We can prepare, in the laboratory, a white powder that proves to be calcium carbonate, that is, it appears to be wholly composed of carbon dioxide and lime. .We find in nature two other unlike substances, marble and Iceland spar, each of which is wholly composed of carbon dioxide and lime.^ A substance carrying one kind of charge attracted another substance carrying the other, but two substances bearing the same kind of charge repelled each other.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ In the equation just cited, for instance, you begin with an atom of C (carbon) and two atoms of O (the oxygen molecule), and you end with an atom of C and two atoms of O (the carbon dioxide molecule).
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Electromagnetic force : one ofthe four forces of nature; particles with electromagnetic charge eitherattract or repel each other depending upon whether the two charges are oppositeor identical.
  • Glossary of Terms for UNH ESPG 2 February 2010 13:34 UTC www-ssg.sr.unh.edu [Source type: FILTERED WITH BAYES]

.Thus these three substances, unlike in appearance and origin, are composed of the, same ingredients: if small variations in the combining ratio of the components were possible, we might expect to find them in such a case as this.^ In 1.9 the two x ’s are not the same variable, so the original x is still 1.

^ In one combination, these gases formed dinitrogen trioxide (N 2 O 3 ), but when he repeated the combination with double the amount of oxygen (a ratio of 1:2), they instead formed nitrogen dioxide (NO 2 ).
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ Thus, none of these atoms have the expected non-blank atom variant field.
  • PDB ATOM format 2 February 2010 13:34 UTC bmerc-www.bu.edu [Source type: FILTERED WITH BAYES]

.But analysis has failed to find such differences; the ratio of the weights of lime and carbon dioxide is found to be the same in all three substances.^ In reality, the nucleus (and the wavefunction of each of the nucleons ) is also spherically symmetric and 1s, and the four particles, each with a different quantum number, like the electrons in the helium atom, are all most likely to be found in the same space, at the exact center of the nucleus.
  • File:Helium atom QM.svg - Wikimedia Commons 2 February 2010 13:34 UTC commons.wikimedia.org [Source type: Reference]

^ Different arrangements of atoms into groups compose all substances.
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

^ Allotrope Atoms can be connected differently, even if they are all atoms of the same element.
  • Glossary 2 February 2010 13:34 UTC www.chem.wisc.edu [Source type: FILTERED WITH BAYES]

.Such analyses, which do not always admit of great accuracy, have been confirmed by a few carefully planned experiments in which two components were brought together under very varied conditions, and the resulting compound analysed.^ Professor Thomson shown that such particles, under the conditions outlined above, arrange themselves into groups of various arrangement, the latter depending on their number.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Apparent Density The ratio of mass to volume of a finely powdered material, under stated conditions, which is always less than true density.

^ A math property which states: A+B=B+A and A*B=B*A. compound Two or more atoms joined together chemically, with covalent or ionic bonds.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

.Stas carried out such experiments on the composition of silver chloride and of ammonium chloride, but he never found a variation of one part in 10,000 in the composition of the substances.^ It will be available in blue, red, and silver and the Aspire One 532h weighs 2.76 pounds and measures 10.2″ x 7.3″ x 1″.

^ Once the relative mass scale was made, later experiments were able to relate the mass in grams of a substance to the number of atoms and an atomic mass unit (amu) was found; 1 amu or Dalton is equal to 1.66 x 10 -24 grams.
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ He carried out reactions in closed vessels so that he could keep track of the amounts of the various reagents involved.

.The two laws discussed above were more or less accepted before the promulgation of the atomic theory, but the law of multiple proportions is the legitimate offspring of this theory.^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ Atoms: By Takalah Topics Covered Law of Multiple Proportions Dalton's Atomic Theory Intro to Atomic Structure Molecules and Ions Compound Naming This section introduces some basic concepts of chemistry.
  • learnchem.net: Atoms Tutorial 2 February 2010 13:34 UTC learnchem.net [Source type: Original source]

^ For most substances, the solid form is more dense than the liquid form and would sink to the bottom of any mixture of the two, but for water, the solid (ice) is less dense.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

.Berzelius saw at once that it afforded an admirable test for the correctness of Dalton's views, and he made numerous experiments expressly designed to test the law.^ Once the relative mass scale was made, later experiments were able to relate the mass in grams of a substance to the number of atoms and an atomic mass unit (amu) was found; 1 amu or Dalton is equal to 1.66 x 10 -24 grams.
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

.One of these experiments may be described.^ Each Aggregation may be described by one or more Resource Maps, each of which must have exactly one Representation that is a serialization of the Resource Map according to a specific format.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ Each Aggregation may be described by one or more Resource Maps, each of which must have exactly one representation that is a serialization of the Resource Map according to a specific format.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]
  • ORE User Guide - Resource Map Implementation in Atom 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ These functions may all be defined in one php file, or maybe spread among more than one file.
  • Glossary « WordPress Codex 2 February 2010 13:34 UTC codex.wordpress.org [Source type: Reference]

.Two chlorides of copper are known, one a highly coloured substance, the other quite white.^ It followed from this law of isomorphism ("same shape") that if two compounds crystallized together and if the structure of only one of them was known, the structure of the second could be assumed to be similar.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ For those textures which are highly tinted towards one color, (such as foliage), it can provide an extra bit or two of precision in the non-dominate color channels.

^ When a substance contained a greater than normal quantity of electric fluid, it possessed one kind of electric charge; when it contained a less than normal quantity, it possessed the other kind.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.Berzelius took 8 grams of copper, converted it into the coloured chloride, and sealed up the whole of this in solution, together with a weighed strip of copper.^ But we run into trouble, because we come upon a related problem and wind up starting the process all over again, fashioning a new solution for this specific problem.
  • Peter Keane's Miscellanea · Atom 2 February 2010 13:34 UTC blogs.law.harvard.edu [Source type: FILTERED WITH BAYES]

^ The metal rods or strips inserted into a melt or solution, he called electrodes ; the electrode carrying a positive charge being an anode , the one carrying a negative charge the cathode .
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

After some time the colour entirely disappeared; the strip of copper was then taken out and reweighed, and it was found to have lost 8.03 grams. .Thus the chlorine, which in the coloured compound was in union with 8 grams of copper, appears, in the colourless chloride, to be combined with 16.03 grams, or almost exactly double the amount.^ In one combination, these gases formed dinitrogen trioxide (N 2 O 3 ), but when he repeated the combination with double the amount of oxygen (a ratio of 1:2), they instead formed nitrogen dioxide (NO 2 ).
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ One volume of hydrogen combines with one volume of chlorine, and it seems reasonable to suppose that the hydrogen chloride molecule is made up of one hydrogen atom combined with one chlorine atom.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Suppose, though, you wished to say that hydrogen combined with chlorine to form hydrogen chloride.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

It is easy to verify this result. .In a series of repetitions of the experiment, by different observers, the following numbers were obtained for the ratio of the copper in the two chlorides: 1.98, 1.97, 2.03, 2.003, the mean value being 1.996. It will be noticed that the ratio found is sometimes above and sometimes below the number 2, which is required by the atomic theory, and therefore the deviations may not unreasonably be attributed to experimental errors.^ Each has the same atomic number but a different mass number.
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ But they may have different number of neutrons.
  • Atoms - un knol de Glenn Lo 2 February 2010 13:34 UTC knol.google.com [Source type: Reference]

^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

.Such experiments - and numerous ones of about this degree of accuracy have been made on a variety of substances - give a high degree of probability to the law, but leave it an open question whether it has the exactitude of the law of the conservation of matter, or whether it is only approximately true.^ About the same time as Thomson's experiments with cathode rays, physicists such as by Henri Becquerel, Marie Curie, Pierre Curie, and Ernest Rutherford were studying radioactivity .
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ Such equations must account for all the atoms if Lavoisier's law of conservation of mass is to be obeyed.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ He gave a list of expected properties of its compounds, such as a tetrachloride of density 1.9 and boiling point about 90 degrees, etc.

The question is, however, vital to the atomic theory. .It is, therefore, worth while to quote a verification of great exactitude from the work of Stas and J. B. A. Dumas' on the composition of the two oxides of carbon.^ First two: 1s 2 Next two: 2s 2 Last two: 2p 2 We can therefore say that carbon has the electron configuration of "[1s 2 2s 2 2p 2 ]".
  • Atomic Structure 2 February 2010 13:34 UTC www.shodor.org [Source type: Academic]
  • Atomic Structure 11 September 2009 3:41 UTC www.shodor.org [Source type: Academic]

From their work it follows that the ratio of the weights of oxygen combined with unit weight of carbon in the two oxides is 1.99995, or with somewhat different data, 1.9996.
.The law of reciprocal proportion, of which some examples have been already given, is part of a larger law of equivalence that underlies most of our chemical methods and calculations.^ For example, in our luminescent tube, the ions and electrons is a small proportion in relation to atoms and molecules.

^ His second law of electrolysis stated: The weight of metal liberated by a given quantity of electricity is proportional to the equivalent weight of the metal.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Nor is it a mandated part of AtomServer, for that matter -- we were simply going with a boiled down URI scheme so we could talk about some concrete examples easily.
  • InfoQ: AtomServer – The Power of Publishing for Data Distribution 2 February 2010 13:34 UTC www.infoq.com [Source type: FILTERED WITH BAYES]

.One section of the law expresses the fact that the weights of two substances, not necessarily elements, that are equivalent in one reaction, are often found to be equivalent in a number of other reactions.^ He found that when electrolysis liberated elements at an electrode, it took always the same total amount of electric current (or some small integer multiple) to liberate one mole of the element (that is, Avogadro's number of atoms).

^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ Berzelius's table seemed to destroy this attractive suggestion (attractive, because it reduced the growing number of elements to one fundamental substance, after the fashion of the ancient Greeks, and thereby seemed to increase the order and symmetry of the universe).
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.The neutralization of acids by bases affords many illustrations, known even before the atomic theory, of the truth of the statement.^ In particular, solutions of acids will neutralize solutions of bases.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Not until 1913 was it known that the atomic number is actually a unit of measurement, equal to the number of electrons surrounding a neutral (uncharged) atom, and also to the number of protons in the nucleus.
  • Units: A 2 February 2010 13:34 UTC www.unc.edu [Source type: Reference]

^ Dalton's atomic theory was based on the assumption that atoms are tiny indivisible entities, with each chemical element consisting of its own characteristic atoms.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

.It is universally found that the weights of two bases which neutralize the same weight of one acid are equivalent in their power of neutralizing other acids.^ In particular, solutions of acids will neutralize solutions of bases.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ It followed from this law of isomorphism ("same shape") that if two compounds crystallized together and if the structure of only one of them was known, the structure of the second could be assumed to be similar.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ For example, he found that when carbon combined with oxygen to form a gas, there were two possible outcomes, depending on the conditions - and in one outcome each gram of carbon combined with precisely twice as much oxygen as in the other.

.Thus 5 parts by weight of soda, 7 of potash and 3.5 of quicklime will each neutralize 4.56 parts of hydrochloric acid or 7.875 of nitric or 6.125 parts of sulphuric acid; these weights, in fact, are mutually equivalent to one another.^ S salts Ionic compounds that can be formed by replacing one or more of the hydrogen ions of an acid with another positive ion.
  • Chemistry Glossary 2 February 2010 13:34 UTC www.shodor.org [Source type: Reference]

^ A change in the behavior of one part of a molecule caused by a change in another part of the molecule.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ Thus, a solution of the strong and caustic acid, hydrochloric acid, if mixed with the proper amount of the strong and caustic alkali, sodium hydroxide, will become a solution of sodium chloride, ordinary table salt.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.The Daltonian would say that each of these weights represents a certain group of atoms, and that these groups can replace, or combine with, each other, to form new molecules.^ When atoms unite to form molecules, they are said to saturate each other.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ These will form a group of definite shape.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Chemical compounds are formed when atoms combine with each other.
  • learnchem.net: Atoms Tutorial 2 February 2010 13:34 UTC learnchem.net [Source type: Original source]
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

.The change from a binary compound, that is, one containing two elements, to a ternary compound in which.^ MUST NOT contain more than one atom:summary element.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

^ Atom Entry elements in Collection Documents SHOULD contain one app:edited element, and MUST NOT contain more than one.
  • The Atom Publishing Protocol 2 February 2010 13:34 UTC bitworking.org [Source type: Reference]
  • RFC 5023 - The Atom Publishing Protocol 2 February 2010 13:34 UTC tools.ietf.org [Source type: Reference]

^ Person constructs MAY contain an atom:uri element, but MUST NOT contain more than one.
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

these two elements are associated with a third, sometimes affords a very good test for the theory. .The atomic theory can picture the change from the binary to the ternary compound simply as the addition of one or more atoms of the third element to the previously existing molecule; in such a case the combining ratio of the first two elements should be absolutely the same in both compounds.^ MUST NOT contain more than one atom:summary element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ An atom cannot exist alone as such.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ MUST NOT contain more than one atom:icon element.
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

Berzelius tested this prediction. .He showed that lead sulphide, a black substance containing only lead and sulphur, could be converted by oxidation into lead sulphate, a white compound containing oxygen as well as lead and sulphur.^ It followed from this law of isomorphism ("same shape") that if two compounds crystallized together and if the structure of only one of them was known, the structure of the second could be assumed to be similar.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ The process of converting nitrogen from the atmosphere into usable nitrogen compounds is called nitrogen "fixing".

^ Once the atomic theory was accepted, one could picture substances as composed of molecules containing a fixed number of atoms of various elements.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.The whole of the lead and sulphur of the sulphide was found to be present in the sulphate; in other words, the combining ratio of the lead and sulphur was not altered by the addition of the oxygen.^ In one combination, these gases formed dinitrogen trioxide (N 2 O 3 ), but when he repeated the combination with double the amount of oxygen (a ratio of 1:2), they instead formed nitrogen dioxide (NO 2 ).
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ They are usually found in chemical combination with other elements as mineral ores.

^ Because most elements tend to combine with others, few elements are found in their pure form.
  • Atoms 2 February 2010 13:34 UTC facstaff.gpc.edu [Source type: FILTERED WITH BAYES]

This is found to be a general rule. .It was verified very exactly by Stas's experiments, in which he removed the oxygen from the ternary compound silver iodate and found that the whole of the silver and the iodine remained in combination with each other as silver iodide; his results prove, to one part in ten millions, that the combining ratio of the silver and the iodine is unaltered by the removal of the oxygen.^ Even if this were so, it remained true that 1 part of hydrogen (by weight) was combined with 8 parts of oxygen.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ In one combination, these gases formed dinitrogen trioxide (N 2 O 3 ), but when he repeated the combination with double the amount of oxygen (a ratio of 1:2), they instead formed nitrogen dioxide (NO 2 ).
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

.The above gives some idea of the evidence that has been accumulated in favour of the laws of chemical combination, laws which can be deduced from the atomic theory.^ The idea of the atom was first devised by Democritus in 530 B.C. In 1808, an English school teacher and scientist named John Dalton proposed the modern atomic theory.
  • Howstuffworks "How Atoms Work" 2 February 2010 13:34 UTC www.howstuffworks.com [Source type: FILTERED WITH BAYES]

^ To put this into scientific terms for all the science minded, Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

^ Atoms: By Takalah Topics Covered Law of Multiple Proportions Dalton's Atomic Theory Intro to Atomic Structure Molecules and Ions Compound Naming This section introduces some basic concepts of chemistry.
  • learnchem.net: Atoms Tutorial 2 February 2010 13:34 UTC learnchem.net [Source type: Original source]

.Whenever any of these laws, or indeed any prediction from the theory, can be tested it has so far proved to be in harmony with experiment.^ Accurate ab initio predictions are an important test of a theory.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

.The existence of the periodic law (see Element), and the 1 Freund, The Study of Chemical Composition. II. 28 a researches of physicists on the constitution of matter, also furnish very strong support to the theory.^ When Mendeleev began grouping elements, he noticed the Law of Chemical Periodicity.
  • Atomic Structure 2 February 2010 13:34 UTC www.shodor.org [Source type: Academic]
  • Atomic Structure 11 September 2009 3:41 UTC www.shodor.org [Source type: Academic]

^ To put this into scientific terms for all the science minded, Periodic Law states that the physical and chemical properties of the elements are periodic functions of their atomic numbers.

^ Mendeleev had the courage to leave gaps where he believed new elements would be discovered - so that the periodic patterns of chemical behavior recurred throughout the table.

.Dalton was of the opinion that it was possible to determine the weights of the elementary atoms in terms of any one by the analysis of compounds.^ Instances of atom:id elements can be compared to determine whether an entry or feed is the same as one seen before.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]

^ Determination of molecular weights by addition of the weights of the atoms that make up the molecule.
  • CHEMISTRY I: ATOMS AND MOLECULES 2 February 2010 13:34 UTC www.emc.maricopa.edu [Source type: Academic]

^ In the 1800's an English chemist, John Dalton performed experiments with various chemicals that showed that matter, indeed, seem to consist of elementary lumpy particles (atoms).
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

.It is evident that this is practicable if the number and kind of atoms contained in the molecule of a compound can be determined.^ An atom contains several kinds of particles.

^ The atomic number determines the identity of an atom.

^ MAY contain any number of atom:link elements with a rel attribute value of " alternate ".
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.To take the simplest possible case, if Dalton had been correct in assuming that the molecule of water was made up of one atom of oxygen and one of hydrogen, then the experimental fact that water contains eight parts by weight of oxygen to one part of hydrogen, would at once show that the atom of oxygen is eight times as heavy as the atom of hydrogen, or that, taking the atomic weight of hydrogen as the unit, the.^ The atom of lowest weight is the hydrogen atom.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ If it was decided to set the weight of the hydrogen atom arbitrarily equal to 1, then the weight of the oxygen atom on that scale would be 8.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ The atoms pair up to form 100 molecules of hydrogen chloride.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

atomic weight of oxygen is .8. Similarly, Dalton's diagram for ammonia, together with the fact that ammonia contains 4.67 parts of nitrogen to one of hydrogen, at once leads to the conclusion that the atomic weight of nitrogen is 4.67. But, unfortunately, the assumption as to the number of atoms in the molecules of these two compounds was an arbitrary one, based on no valid evidence.^ It could also be argued from similar lines of evidence that the ammonia molecule did not consist of a combination of one nitrogen atom and one hydrogen atom, but of one nitrogen atom and three hydrogen atoms.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Molecular weight equals the sum of the atomic weights of the atoms in the molecule.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

^ From that evidence one could conclude that the atomic weight of nitrogen was not nearly 5, but was 14.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.It is now agreed that the molecule of water contains two atoms of hydrogen and one of oxygen, so that the atomic weight of oxygen becomes 16, and similarly that the molecule of ammonia contains three atoms of hydrogen and one of nitrogen, and that consequently the atomic weight of nitrogen is 14. On account of this difficulty, the atomic weights published by Dalton, and the more accurate ones of Berzelius, were not always identical with the values now accepted, but were often simple multiples or submultiples of these.^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The atom of lowest weight is the hydrogen atom.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ MUST NOT contain more than one atom:icon element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.The "symbols" for the elements used by Dalton, apparently suggested by those of the alchemists, have been rejected in favour of those which were introduced by Berzelius.^ The creation and modification times of the Aggregation (distinct from those of the Resource Map) are provided using /entry/category elements.
  • ORE User Guide - Resource Map Implementation in Atom 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

^ The first four dots are arranged on the four sides of the elemental symbol, and any remaining dots are arranged pairwise with those already present.
  • Glossary 2 February 2010 13:34 UTC www.chem.wisc.edu [Source type: FILTERED WITH BAYES]

^ One way molecules can be represented is by a chemical formula where symbols for the elements are used to indicate the types of atoms present and subscripts are used to indicate the relative numbers of atoms.
  • Glossary 2 February 2010 13:34 UTC www.chem.wisc.edu [Source type: FILTERED WITH BAYES]

.The Formulae. latter employed the first letter, or the first two letters, of the name of an element as its symbol.^ Each element has a symbol made of the first letter or two of its name.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

^ The first letter of the symbol is capitalized and the second letter, if there is one, must be written in lower case.
  • Atoms - un knol de Glenn Lo 2 February 2010 13:34 UTC knol.google.com [Source type: Reference]

^ As a matter of convenience, elements are assigned symbols that are derived from their names.
  • Atoms - un knol de Glenn Lo 2 February 2010 13:34 UTC knol.google.com [Source type: Reference]

.The symbol, like that of Dalton, always stands for the atomic weight of the element, that is, while H stands for one part by weight of hydrogen, 0 stands for 16 parts of oxygen, and so on.^ It is called the atomic number and is given the symbol Z. Hydrogen is the simplest element and has Z = 1.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

^ On this oxygen = 16 standard, the atomic weight of hydrogen was equal, roughly, to 1.008.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ For instance, 1 part (by weight) of hydrogen combined with 8 parts of oxygen to form water.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.The symbols of compounds become very concise, as the number of atoms of one kind in a molecule can be expressed by a sub-index.^ It is easy to use these symbols to indicate the number of atoms in a molecule.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ One volume of hydrogen combines with one volume of chlorine, and it seems reasonable to suppose that the hydrogen chloride molecule is made up of one hydrogen atom combined with one chlorine atom.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Each element has a unique atomic number and its atoms have one more proton and one more electron than the atoms of the element that precedes it in the list.
  • Elements and Atoms 2 February 2010 13:34 UTC users.rcn.com [Source type: FILTERED WITH BAYES]

.Thus the symbol or formula H 2 O for water expresses the view that the molecule of water consists of one atom of oxygen and two of hydrogen; and if we know the atomic weights of oxygen and hydrogen, it also tells us the composition of water by weight.^ The atom of lowest weight is the hydrogen atom.
  • CATHOLIC ENCYCLOPEDIA: Atom 2 February 2010 13:34 UTC www.newadvent.org [Source type: FILTERED WITH BAYES]

^ Molecular weight equals the sum of the atomic weights of the atoms in the molecule.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

^ If one assumed that a molecule of water consisted of one atom of hydrogen and one atom of oxygen, then it would follow that the oxygen atom was eight times as heavy as the hydrogen atom.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

Similarly, the modern formula for ammonia is NH3.
.The superiority of this notation over that of Dalton is not so obvious when we consider such simple cases as the above, but chemists are now acquainted with very complex molecules containing numerous atoms; cane sugar, for example, has the formula C 12 H 22 0, 1. It would be a serious business to draw a Daltonian diagram for such a molecule.^ The formula for glucose ( a very common sugar) is C 6 H 12 O 6 .
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

^ On putting together data on many different reactions, it became apparent to Dalton that the rule of greatest simplicity wasn't necessarily correct, by 1810 he was suggesting that the water molecule perhaps contained three atoms.

^ Intermediaries such as aggregators may need to add an atom:source element to an entry that does not contain its own atom:source element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]

.Dalton believed that the molecules of the elementary gases consisted each of one atom; his diagram for hydrogen gas makes the point clear.^ It is not a high point, but it makes one smile.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ These turn out to make the process be a complete cycle, one that starts at a much earlier point than anyone but the villain realized.
  • The Atom 19 January 2010 8:48 UTC mikegrost.com [Source type: FILTERED WITH BAYES]

^ However, we do not believe that this all-in-one approach provides a reliable basis for full validation of atom and its extensions.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

.We now believe that the molecule of an element is frequently made up of two or more atoms; thus the formulae for the gases hydrogen, oxygen and nitrogen are 112, 02, N2, while gaseous phosphorus and sulphur are probably P4 and S 6, and gaseous mercury is Hg i, - that is, the molecule of this element is monatomic.^ The two possible ions with mercury are Hg 2+ 2 2+ .
  • learnchem.net: Atoms Tutorial 2 February 2010 13:34 UTC learnchem.net [Source type: Original source]

^ An Atom feed is made up of standardized elements.
  • Cover Pages: Atom Publishing Format and Protocol 2 February 2010 13:34 UTC xml.coverpages.org [Source type: FILTERED WITH BAYES]

^ The atoms pair up to form 100 molecules of hydrogen chloride.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

.This view, as to the frequently complex nature of the elementary molecule, is logically and historically connected with the striking hypothesis of Amadeo Avogadro and A. M. Ampere.^ For one thing, if one volume of oxygen combined with hydrogen to form two volumes of water, it looked to Dalton as if the water molecules each had half an oxygen atom, if we believe Avogadro's hypothesis.

.These natural philosophers suggested that equal volumes of all gaseous substances must contain, at the same temperature and pressure, the same number of molecules.^ Avogadro was the first to conclude from Dalton's atomic theory that equal volumes of gases (at the same temperature and pressure) must contain equal number of molecules.
  • Units: A 2 February 2010 13:34 UTC www.unc.edu [Source type: Reference]

^ For example, 1 L of ideal gas contains twice as many molecules as 0.5 L of ideal gas at the same temperature and pressure.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ Equal volumes of an ideal gas contain equal numbers of molecules, if both volumes are at the same temperature and pressure.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

.Their hypothesis explains so many facts that it is now considered to be as well established as the parts of the theory due to Dalton.'^ Bohr's theory was in close agreement with many experimental facts regarding one-electron atoms (the hydrogen atom and hydrogen-like atoms, such as He + and Li 2+ ), but it could not explain the "fine structure" of the spectral lines; that is, the fact that certain lines were actually a set of closely spaced lines.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

^ Centuries later, in 1803, the English chemist John Dalton, guided by the experimental fact that chemical elements cannot be decomposed chemically, was led to formulate his atomic theory.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

^ Water has many unique properties due, in great part, to its hydrogen bonding.
  • Atoms, Molecules, Water, and pH 2 February 2010 13:34 UTC biology.clc.uc.edu [Source type: FILTERED WITH BAYES]

.This principle at once enables the weights of molecules to be compared even when their composition is unknown; it is only 1 It will be seen that in the three gas diagrams of Dalton that are reproduced above, equal numbers of molecules are contained in equal volumes, but if Dalton held this view at one time he certainly afterwards abandoned it.^ (A century after Dalton's time this view had to be modified.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Equal volumes of an ideal gas contain equal numbers of molecules, if both volumes are at the same temperature and pressure.
  • General Chemistry Online: Glossary: 19 January 2010 8:48 UTC antoine.frostburg.edu [Source type: Academic]

^ The nucleus occupies less than one thousand million millionth (10 ) of the atomic volume, but contains almost all of the atom's mass.
  • History of atoms 2 February 2010 13:34 UTC www.nobeliefs.com [Source type: FILTERED WITH BAYES]

necessary to determine the specific gravities of the various gases referred to some one of them, say hydrogen; the numbers so obtained giving the weights of the molecules referred to that of the hydrogen molecule.
.The atomic theory has been of priceless value to chemists, but it has more than once happened in the history of science that a hypothesis, after having been useful in the discovery Present and the co-ordination of knowledge, has been aban- position doned and replaced by one more in harmony with later of the discoveries.^ History of atomic theory .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ He deduced this after the experimental discovery of the law of multiple proportions — that is, if two elements form more than one compound between them, then the ratios of the masses of the second element which combine with a fixed mass of the first element will be ratios of small whole numbers .
  • Atom - Free net encyclopedia 2 February 2010 13:34 UTC www.netipedia.com [Source type: Reference]

^ MUST NOT contain more than one atom:summary element.
  • The Atom Syndication Format 2 February 2010 13:34 UTC atompub.org [Source type: Reference]
  • ietf-atompub-format-11.txt 2 February 2010 13:34 UTC ietfreport.isoc.org [Source type: Reference]
  • ORE Specification - Representing Resource Maps Using the Atom Syndication Format 2 February 2010 13:34 UTC www.openarchives.org [Source type: Reference]

.Some distinguished chemists have thought atomic that this fate may be awaiting the atomic theory, and that in future chemists may be able to obtain all the guidance they need from the science of the transformations of energy.^ Nuclear energy Development of atomic theory .
  • atom (matter) -- Britannica Online Encyclopedia 19 January 2010 8:48 UTC www.britannica.com [Source type: Academic]

^ Centuries later, in 1803, the English chemist John Dalton, guided by the experimental fact that chemical elements cannot be decomposed chemically, was led to formulate his atomic theory.
  • Atomic Structure - Chemistry Encyclopedia - Modern View of the Atom, Bohr Model of the Atom 11 September 2009 3:41 UTC www.chemistryexplained.com [Source type: Academic]

^ If the person tries to control them (which he or she may be able to do for the short time), it will cause internal anxiety and they will need to spend several minutes ‘tic-ing’ to ‘get it out of their system.’ .
  • Stan Gardner, M.D. — Healthy Alternatives to Drugs and Surgery 2 February 2010 13:34 UTC www.stangardnermd.com [Source type: FILTERED WITH BAYES]

.But modern discoveries in radioactivity 2 are in favour of the existence of the atom, although they lead to the belief that the atom is not so eternal and unchangeable a thing as Dalton and his predecessors imagined, and in fact, that the atom itself may be subject to that eternal law of growth and decay of which Lucretius speaks.^ The ancient Greek philosophers developed the concept of the atom, although they considered it the fundamental particle that could not be broken down.
  • CHEMISTRY I: ATOMS AND MOLECULES 2 February 2010 13:34 UTC www.emc.maricopa.edu [Source type: Academic]

^ Furthermore, from the fact that the law of definite proportions was an observed fact, one could deduce that atoms were indeed indivisible objects.
  • Atoms 2 February 2010 13:34 UTC www.3rd1000.com [Source type: FILTERED WITH BAYES]

^ Beta particle: A particle emitted from an atom during radioactive decay.
  • World Nuclear Association Glossary 2 February 2010 13:34 UTC www.world-nuclear.org [Source type: Reference]

(F. H. NE.)


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also atom

Contents

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Noun

Atom n. (genitive Atoms, plural Atome)
  1. atom

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Citable sentences

Up to date as of December 13, 2010

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