What atomic particle gives an atom it it's chemical properties?
a. protons
b. isotopes
c. electrons
d. neutrons

All of the atom's day-to-day relationship with the outside world is exclusively the business of the electrons. The protons and neutrons are buried waaay down inside the atom, in the nucleus, and they never feel anything until you start talking about high-energy events that can smash or crush the nucleus. Isotopes are something else, not atomic particles.