During oxidation, which of the following is true? A. Electrons are gained, so the oxidation number increases. B. Electrons are g
ained, so the oxidation number decreases. C. Electrons are given off, so the oxidation number increases. D. Electrons are given off, so the oxidation number decreases.
Oxidation is when the overall charge (or oxidation number) increases. The only way to increase an oxidation number is to lose an electron, thereby making the negative charges less. The correct answer is C.