Question

Most of the mass of an atom is contained in its _____. A. electrons B. protons C. nucleus D. neutrons

Answer 1

Atom is made up of NUCLEUS and electrons revolving around nucleus.

Nucleus itself contains protons and neutrons. Protons and neutrons are approximately 1680 times heavier than the electrons. So the major contribution to the mass of an atom comes from the nucleus.

Answer is C.