Multiple Oxidation States. Truman Chemistry Dept. Oxidation States can change during a reaction. Example: Oxidation state of oxygen CH 4 + 2O 2 CO 2 + 2H 2 O In O 2 the oxidation state of O is zero In CO 2 and H 2 O the oxidation state of O is -2
Truman Chemistry Dept.
All elements in a diatomic molecule have an oxidation state of zero (they are neutral) ie. Cl2
If an element is monatomic (by itself) the charge is only as specified (ie. Cl-). Free elements have a charge of zero (ie. Fe)
All neutral compounds must have a net (total) oxidation charge of zero and the element with the highest electronegativity (furthest right on table) is the negative element.Rules
(1) +1 (2) +2 (3) -1 (4) -2
(1) -2 (2) +2 (3) -4 (4) +4