Definition Of Oxidation Numbers. The oxidation number could be positive, negative, or zero, and it indicates if electrons are lost or gained. Assign oxidation numbers to each element in all the compounds or ions.

Assign oxidation numbers to each element in all the compounds or ions. For simple atoms or ions the oxidation number is equal to the ionic charge. An oxidation number definition is a number assigned to a compound or element to show how many electrons were lost or gained.