Here are a few rules to remember when solving for oxidation state.
(1) The total charge of a stable compound is always equal to zero (meaning no charge).
For example, the
(2) If the substance is an ion (either there is a positive or negative charge) the total oxidation state of the ion is the charge (i.e. oxidation state of
(3) All elements from Group 1A has an oxidation state of +1 (e.g.
(4) Oxygen always have a charge -2 except for peroxide ion (
(5) Hydrogen always have a charge of +1 if it is bonded with a non-metal (as in the case of
Now let's solve your problem.
Based on rule 2, the oxidation state of the
based on rule 4, the oxidation state of
Notice that since
Therefore your oxidation states are