Half equation

A half equation represents either electron gain or electron loss.

A half equation represents the change at just one electrode. It names the reacting ion or atom, the product formed and the electrons transferred. A complete electrolysis process therefore has two half equations: one for the reaction at the cathode and one for the reaction at the anode.

A half-equation focuses on what happens to one reactant, often an ion at an electrode. Because electrons carry charge, a half-equation must balance both atoms and total electrical charge.

A half equation represents one of these electrode changes. It shows the reacting ion, the substance formed and the electrons transferred.