The correct answer is protons and electrons.
Atoms are made of particles called protons (p+), neutrons (n0), and electrons (e-).
Protons and neutrons are located in the center of the atom, making up the nucleus and electrons surround the nucleus.
The charge on the proton and electron are exactly the same size but opposite and their number in the atom is the same when we talk about neutral atoms. Ions are charged atoms, so the number of their electrons and protons are different (for example, positive ions have more protons).
