Answer: Loss of electrons.
- A Gain of electrons
- B Gain of protons
- C No net change
- D Loss of electrons
Correct answer: D. Loss of electrons
Explanation: Oxidation is loss of electrons (increase in oxidation number); reduction is gain of electrons.
Electron transfer in a redox reaction: zinc loses electrons (oxidised, acts as reducing agent) and copper(II) ions gain those same electrons (reduced, acts as oxidising agent).
Concept context
Master electron transfer in chemistry: assign oxidation states, balance half-reactions, identify oxidising and reducing agents, and connect redox to everyday reactions.