Oxidation State Rules

Oxidation State Rules
Pure elements are all zero.
Fluorine is -1.
Metals: 1A are +1, 2A are +2, and aluminum is +3.
H is usually +1 (when in a compound with a non-metal), is –1 when in a compound with a less electronegative metal (hydride).
Oxygen is usually –2.
Group 7A elements (halogens) are -1.