Oxidation States: Electron Bookkeeping

• In order to identify oxidation and reduction, chemists have devised a scheme of oxidation states to track electrons in chemical reactions.
• In this scheme—which is like bookkeeping for electrons—all shared electrons are assigned to the most electronegative element.
• Then a number—called the oxidation state or the oxidation number—is computed for each element based on the number of electrons assigned to it.
• Do not confuse oxidation state with ionic charge. A substance need not be ionic to have an assigned oxidation state.
• The easiest way to assign oxidation states is to follow the rules for assigning oxidation states.