A molecule becomes oxidized when it __________.

• A. loses protons
• B. gains neutrons
• C. loses electrons
• D. gains electrons

Answer: (C)

Verified step by step guidance

1. Understand the concept of oxidation in chemistry: Oxidation refers to the loss of electrons by a molecule, atom, or ion.
2. Recall that oxidation and reduction always occur together in redox reactions; when one species loses electrons (oxidized), another gains electrons (reduced).
3. Recognize that losing protons (H⁺ ions) or gaining neutrons does not define oxidation; these are different processes unrelated to electron transfer.
4. Identify that gaining electrons corresponds to reduction, the opposite of oxidation.
5. Conclude that the correct definition of oxidation is when a molecule loses electrons.