If the oxidation number of an atom decreases, the atom has undergone oxidation. a. true b. false

Oxidation is a process when an atom, a group of atoms, or an ion loses electrons.

For example,

Cu⁰ > Cu⁺² + 2e⁻. This is an oxidation process.

As we can see an oxidation number was 0, and it became +2. The oxidation number is increased. Oxidation number of the atom, when an atom has undergone oxidation, increases.

So, answer is b.False.