Editing Chemistry (section)

===Ions and salts===
[[File:Potassium-chloride-3D-ionic.png|thumb|upright=0.75|The crystal lattice structure of [[potassium chloride]] (KCl), a salt which is formed due to the attraction of K<sup>+</sup> cations and Cl<sup>−</sup> anions. The overall charge of the ionic compound is zero.]]
{{Main|Ion}}

An ''ion'' is a charged species, an atom or a molecule, that has lost or gained one or more electrons. When an atom loses an electron and thus has more protons than electrons, the atom is a positively charged ion or [[cation]]. When an atom gains an electron and thus has more electrons than protons, the atom is a negatively charged ion or [[anion]]. Cations and anions can form a crystalline lattice of neutral [[salt (chemistry)|salts]], such as the Na<sup>+</sup> and Cl<sup>−</sup> ions forming [[sodium chloride]], or NaCl. Examples of [[polyatomic ion]]s that do not split up during [[acid–base reaction]]s are [[hydroxide]] (OH<sup>−</sup>) and [[phosphate]] (PO<sub>4</sub><sup>3−</sup>).

[[plasma (physics)|Plasma]] is composed of gaseous matter that has been completely ionized, usually through high temperature.