Changes

Molecules are distinguished from [[polyatomic ion]]s in the strict sense.

Molecules are distinguished from [[polyatomic ion]]s in the strict sense.

This definition has evolved as knowledge of the structure of molecules has increased.  Earlier definitions were less precise defining molecules as the smallest [[list of particles#Molecules|particles]] of pure [[chemical substance]]s that still retain their [[chemical compound|composition]] and chemical properties. [http://antoine.frostburg.edu/chem/senese/101/glossary/m.shtml#molecule Molecule Definition]  (Frostburg State University)</ref> This definition often breaks down since many substances in ordinary experience, such as [[rock (geology)|rock]]s, [[salt]]s, and [[metal]]s, are composed of atoms or [[ion]]s, but are not made of molecules.

This definition has evolved as knowledge of the structure of molecules has increased.  Earlier definitions were less precise defining molecules as the smallest [[list of particles#Molecules|particles]] of pure [[chemical substance]]s that still retain their [[chemical compound|composition]] and chemical properties. [http://antoine.frostburg.edu/chem/senese/101/glossary/m.shtml#molecule Molecule Definition]  (Frostburg State University). This definition often breaks down since many substances in ordinary experience, such as [[rock (geology)|rock]]s, [[salt]]s, and [[metal]]s, are composed of atoms or [[ion]]s, but are not made of molecules.

In the [[kinetic theory]] of [[gas]]es the term ''molecule'' is often used for any gaseous particle regardless of their composition.<ref>E.g. see [http://www.usd.edu/phys/courses/phys_111sf/ch_10/10_notes.htm] According to this definition [[noble gas]]es would also be considered ''molecules'' despite the fact that they are composed of a single non-bonded atom.

In the [[kinetic theory]] of [[gas]]es the term ''molecule'' is often used for any gaseous particle regardless of their composition.E.g. see [http://www.usd.edu/phys/courses/phys_111sf/ch_10/10_notes.htm] According to this definition [[noble gas]]es would also be considered ''molecules'' despite the fact that they are composed of a single non-bonded atom.

== History ==

== History ==