Oxidation & Reduction

The term redox is used for the simultaneous processes of oxidation and reduction.

Oxidation is the loss of electrons.

Reduction is the gain of electrons.

Any reaction which involves reduction also involves oxidation. Therefore these reactions are called redox reactions.

The atom that loses electrons is oxdised, and the atom that gains electrons is reduced.

Oxidation is an increase in oxidation number.

Reduction is a decrease in oxidation number.

An oxidising agent removes electrons, a reducing agent donates electrons. Or another way; a reducing agent gets oxidised and an oxidising agent gets reduced.