Wat (wie) is ATOM - definitie
![hydrogen-like]] atomic orbitals showing probability density and phase ('''g''' orbitals and higher are not shown)](https://commons.wikimedia.org/wiki/Special:FilePath/Atomic-orbital-clouds spdf m0.png?width=200 "hydrogen-like]] atomic orbitals showing probability density and phase ('''g''' orbitals and higher are not shown)")
![These electron's energy levels (not to scale) are sufficient for ground states of atoms up to [[cadmium]] (5s<sup>2</sup> 4d<sup>10</sup>) inclusively. Do not forget that even the top of the diagram is lower than an unbound electron state.](https://commons.wikimedia.org/wiki/Special:FilePath/Atomic orbital energy levels.svg?width=200 "These electron's energy levels (not to scale) are sufficient for ground states of atoms up to [[cadmium]] (5s<sup>2</sup> 4d<sup>10</sup>) inclusively. Do not forget that even the top of the diagram is lower than an unbound electron state.")
![100]]) surface. The surface atoms deviate from the bulk [[crystal structure]] and arrange in columns several atoms wide with pits between them (See [[surface reconstruction]]).](https://commons.wikimedia.org/wiki/Special:FilePath/Atomic resolution Au100.JPG?width=200 "100]]) surface. The surface atoms deviate from the bulk [[crystal structure]] and arrange in columns several atoms wide with pits between them (See [[surface reconstruction]]).")
![The [[binding energy]] needed for a nucleon to escape the nucleus, for various isotopes](https://commons.wikimedia.org/wiki/Special:FilePath/Binding energy curve - common isotopes.svg?width=200 "The [[binding energy]] needed for a nucleon to escape the nucleus, for various isotopes")
![Graphic illustrating the formation of a [[Bose–Einstein condensate]]](https://commons.wikimedia.org/wiki/Special:FilePath/Bose Einstein condensate.png?width=200 "Graphic illustrating the formation of a [[Bose–Einstein condensate]]")
![Atoms and molecules as depicted in [[John Dalton]]'s ''A New System of Chemical Philosophy'' vol. 1 (1808)](https://commons.wikimedia.org/wiki/Special:FilePath/Daltons symbols.gif?width=200 "Atoms and molecules as depicted in [[John Dalton]]'s ''A New System of Chemical Philosophy'' vol. 1 (1808)")
![The [[Geiger–Marsden experiment]]:<br /> ''Left:'' Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection.<br /> ''Right:'' Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus.](https://commons.wikimedia.org/wiki/Special:FilePath/Geiger-Marsden experiment expectation and result.svg?width=200 "The [[Geiger–Marsden experiment]]:<br /> ''Left:'' Expected results: alpha particles passing through the plum pudding model of the atom with negligible deflection.<br /> ''Right:'' Observed results: a small portion of the particles were deflected by the concentrated positive charge of the nucleus.")
![Periodic table showing the origin of each element. Elements from carbon up to sulfur may be made in small stars by the [[alpha process]]. Elements beyond iron are made in large stars with slow neutron capture ([[s-process]]). Elements heavier than iron may be made in neutron star mergers or supernovae after the [[r-process]].](https://commons.wikimedia.org/wiki/Special:FilePath/Nucleosynthesis periodic table.svg?width=200 "Periodic table showing the origin of each element. Elements from carbon up to sulfur may be made in small stars by the [[alpha process]]. Elements beyond iron are made in large stars with slow neutron capture ([[s-process]]). Elements heavier than iron may be made in neutron star mergers or supernovae after the [[r-process]].")
![A potential well, showing, according to [[classical mechanics]], the minimum energy ''V''(''x'') needed to reach each position ''x''. Classically, a particle with energy ''E'' is constrained to a range of positions between ''x''<sub>1</sub> and ''x''<sub>2</sub>.](https://commons.wikimedia.org/wiki/Special:FilePath/Potential energy well.svg?width=200 "A potential well, showing, according to [[classical mechanics]], the minimum energy ''V''(''x'') needed to reach each position ''x''. Classically, a particle with energy ''E'' is constrained to a range of positions between ''x''<sub>1</sub> and ''x''<sub>2</sub>.")
![Illustration of a nuclear fusion process that forms a deuterium nucleus, consisting of a proton and a neutron, from two protons. A [[positron]] (e<sup>+</sup>)—an [[antimatter]] electron—is emitted along with an electron [[neutrino]].](https://commons.wikimedia.org/wiki/Special:FilePath/Wpdms physics proton proton chain 1.svg?width=200 "Illustration of a nuclear fusion process that forms a deuterium nucleus, consisting of a proton and a neutron, from two protons. A [[positron]] (e<sup>+</sup>)—an [[antimatter]] electron—is emitted along with an electron [[neutrino]].")
Wikipedia
The name Atom applies to a pair of related Web standards. The Atom Syndication Format is an XML language used for web feeds, while the Atom Publishing Protocol (AtomPub or APP) is a simple HTTP-based protocol for creating and updating web resources.
Web feeds allow software programs to check for updates published on a website. To provide a web feed, the site owner may use specialized software (such as a content management system) that publishes a list (or "feed") of recent articles or content in a standardized, machine-readable format. The feed can then be downloaded by programs that use it, like websites that syndicate content from the feed, or by feed reader programs that allow internet users to subscribe to feeds and view their content.
A feed contains entries, which may be headlines, full-text articles, excerpts, summaries or links to content on a website along with various metadata.
The Atom format was developed as an alternative to RSS. Ben Trott, an advocate of the new format that became Atom, believed that RSS had limitations and flaws—such as lack of on-going innovation and its necessity to remain backward compatible—and that there were advantages to a fresh design.
Proponents of the new format formed the IETF Atom Publishing Format and Protocol Workgroup. The Atom Syndication Format was published as an IETF proposed standard in RFC 4287 (December 2005), and the Atom Publishing Protocol was published as RFC 5023 (October 2007).
