Anion vs. Cation

Ions result from atoms or molecules that have gained or lost one or more valence electrons, giving them a positive or negative charge. Those with a negative charge are called anions and those with a positive charge are called cations. These opposing charges frequently result in ionic bonds with one another.

An anion is an ion that carries a negative charge, causing it to migrate to the anode (positive electrode) in electrolysis. It has more electrons than protons, resulting in the negative charge. Anions are nonmetals.

A cation is an ion that carries a positive charge, causing it to migrate to the cathode (negative electrode) in a electrolysis. It has more protons than electrons, resulting in the positive charge. Cations are metals.

A net negative charge (anion) is indicated with a superscript - after the chemical formula, such as OH^-. A net positive charge (cation) is indicated with a superscript + after the chemical formula, such as NH₄⁺.