Use in C. 3-Zumdahl [9-13-00]

All uncombined elements have oxidation numbers of ZERO.

A.)All elements in a compound have oxidation numbers that sum to zero.

B.) All elements in a polyatomic ion have oxidation numbers that sum to the charge on the ion.

All alkali metals (IA) have an oxidation number of +1, in compounds.

All alkaline-earth elements have an oxidation number of +2.

Fluorine displays an oxidation number of –1.

Oxygen most commonly shows an oxidation number of –2. Notable exceptions are:

with fluorine, oxygen has a charge of +2.

In peroxides, oxygen has an oxidation number of –1 (O₂^-2).

In superoxides, oxygen has a charge of –1/2.

Hydrogen commonly shows an oxidation number of +1. In hydrides (metal + hydrogen compounds), H shows an oxidation number of –1.