When a substance is oxidized it - JAMB Chemistry 2023 Question

When a substance is oxidized, it loses electrons. Oxidation is a process in which a substance loses electrons, and the term "LEO" (Loses Electrons Oxidation) is often used to remember this concept.

"Loses electrons," is the correct description of the oxidation process. In contrast, gaining oxygen atoms or gaining electrons is associated with reduction, not oxidation. Losing protons (H+ ions) is not a typical aspect of oxidation.