Cation Definition and Examples

A cation is an ionic species with a positive charge. The word cation comes from the Greek word kato, which means down. A cation has more protons than electrons, giving it a net positive charge. Cations with multiple charges may be given special names. For example, a cation with a 2 charge is a dication. One with a 3 charge is a trication. A zwitterion has both positive and negative charges at different regions of the molecule, yet an overall neutral charge. The symbol for a cation is the element symbol or molecular formula, followed by a superscript of the charge. The number of the charge is given first, followed by a plus symbol. If the charge is one, the numeral is omitted. Examples of Cations Cations may be either ions of atoms or of molecules. Examples include: AgAl3Ba2Ca2HH3OLiMg2NH4