Using the principles of the Gold Foil Experiment, explain why most of the mass of an atom is concentrated in the nucleus.

• A. The nucleus is made of empty space and photons, which contain most of the atom’s mass.
• B. The nucleus is made of rapidly moving electrons, which contribute most of the atom’s mass.
• C. The nucleus contains protons and neutrons, which are much heavier than electrons.
• D. The nucleus is made of protons and electrons, which contain most of the atom’s mass.

Answer: (C)