a heavier nucleus. a greater atomic mass. more electrons than protons. more electrons than neutrons.
I gave my students this multiple choice question: A negatively-charged ion has

Only one answer is correct among these 4 choices:
- a heavier nucleus.
- a greater atomic mass.
- more electrons than protons.
- more electrons than neutrons.

Could you tell me which one is correct?

more electrons than protons.