Which particles can only be found in the nucleus of an atom?

• A. Electrons, only
• B. Neutrons only
• C. Protons and Neutrons
• D. Protons only

Answer: (C)

In atoms, the nucleus is the tiny, dense center that contains the protons and neutrons, collectively called nucleons. The electrons sit in surrounding regions called orbitals, held in place by the electrostatic attraction to the positively charged nucleus. Because of this arrangement, electrons exist outside the nucleus, while protons and neutrons stay inside.

Therefore, the particles that can only be found in the nucleus are protons and neutrons. The other options don’t fit because electrons are not located in the nucleus, and singling out only protons would ignore the neutrons, while singling out only neutrons would ignore the protons.