Oxidation state

Definition

The oxidation state, or oxidation number, indicates the degree of oxidation of an atom in a chemical compound. It is represented as a positive or negative integer that reflects the number of electrons lost or gained by an atom.

5 Must Know Facts For Your Next Test

1. Oxidation states help determine how electrons are transferred in chemical reactions.
2. The sum of oxidation states in a neutral compound is always zero.
3. In ions, the sum of the oxidation states equals the ion’s charge.
4. Hydrogen typically has an oxidation state of +1, and oxygen usually has an oxidation state of -2.
5. Transition metals can have multiple possible oxidation states.

Review Questions

• What is the typical oxidation state of hydrogen and oxygen in most compounds?
• How do you determine the sum of oxidation states for atoms in a neutral molecule?
• Can transition metals have more than one possible oxidation state? Provide an example.

Related terms

Redox Reaction: A chemical reaction involving the transfer of electrons between two species, resulting in changes in their oxidation states.

Reducing Agent: A substance that donates electrons to another substance, reducing its own oxidation state while oxidizing another.

Oxidizing Agent: A substance that accepts electrons from another substance, increasing its own oxidation state while reducing another.