Oxidation and Reduction:

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When forming compounds, it is important to know something about the way atoms will react with each other. One of the most important manners in which atoms and/or molecules react with each other is the oxidation/reduction reaction. Oxidation/Reduction reactions are the processes of losing and gaining electrons respectively. Just remember, "LEO the lion says GER:" Lose Electrons Oxidation, Gain Electrons Reduction. Oxidation numbers are assigned to atoms and compounds as a way to tell scientists where the electrons are in a reaction. It is often referred to as the "charge" on the atom or compound. The oxidation number is assigned according to a standard set of rules. They are as follows:

1. For single atoms in an ion, their oxidation number is equal to their charge.
2. An atom of a pure element has an oxidation number of zero.
3. Cl, Br, and I are always -1 in compounds except when they are combined with O or F.
4. H is normally +1 and O is normally -2.
5. Fluorine is always -1 in compounds.
6. The oxidation number of a compound is equal to the sum of the oxidation numbers for each atom in the compound.
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