102,815
edits
Changes
no edit summary
[[Image:lighterstill.jpg]]
[[Image:lighterstill.jpg]]
[[Image:Helium_atom_QM.svg.png|right]]
[[Image:Helium_atom_QM.svg.png|right|thumb|This illustrates the [[atomic nucleus|nucleus]] (pink) and the [[electron cloud]] distribution (black) of the [[Helium]] atom. The nucleus (upper right) is in reality spherically symmetric, although this is not always the case for more complicated nuclei.]]
In [[chemistry]] and [[physics]], an '''atom''' ([[Greek language|Greek]] ''ἄτομος'' or ''átomos'' meaning "indivisible") is the smallest particle still characterizing a [[chemical element]]."Atom" in IUPAC Compendium of Chemical Terminology, Electronic version, [http://goldbook.iupac.org/A00493.html].
In [[chemistry]] and [[physics]], an '''atom''' ([[Greek language|Greek]] ''ἄτομος'' or ''átomos'' meaning "indivisible") is the smallest particle still characterizing a [[chemical element]]."Atom" in IUPAC Compendium of Chemical Terminology, Electronic version, [http://goldbook.iupac.org/A00493.html].
The father of modern atomic theory was a Jesuit priest, [[Ruggero Boscovich]], who based his theory mostly on [[classical mechanics]] ([[Isaac Newton|Newtonian]] mechanics) and published it in [[1758]]. The theory was further developed by [[Amedeo Avogadro]], his brother Johann Avogadro and the developers of the [[kinetic theory of gases]] such as [[James Clerk Maxwell]] and physicist [[Ludwig Boltzmann]]. Boscovich was regarded as the father of modern atomic theory by Faraday, Mendeleev, Maxwell, and Kelvin, who observed that his and the work of others' were "all developments of Boscovich's theory pure and simple."
The father of modern atomic theory was a Jesuit priest, [[Ruggero Boscovich]], who based his theory mostly on [[classical mechanics]] ([[Isaac Newton|Newtonian]] mechanics) and published it in [[1758]]. The theory was further developed by [[Amedeo Avogadro]], his brother Johann Avogadro and the developers of the [[kinetic theory of gases]] such as [[James Clerk Maxwell]] and physicist [[Ludwig Boltzmann]]. Boscovich was regarded as the father of modern atomic theory by Faraday, Mendeleev, Maxwell, and Kelvin, who observed that his and the work of others' were "all developments of Boscovich's theory pure and simple."
In 1803, [[John Dalton]] used the concept of atoms to explain why elements always reacted in [[Law of multiple proportions|simple proportions]], and why certain gases dissolved better in water than others. He proposed that each element consists of atoms of a single, unique type, and that these atoms could join to each other, to form compound chemicals.
In 1803, [[John Dalton]] used the concept of atoms to explain why elements always reacted in [[Law of multiple proportions|simple proportions]], and why certain gases dissolved better in water than others. He proposed that each element consists of atoms of a single, unique type, and that these atoms could join to each other, to form compound chemicals.