What was the major discovery made by Rutherford in his gold foil experiment?

• A. Atoms are indivisible and solid spheres.
• B. Electrons are arranged in fixed orbits around the nucleus.
• C. Atoms have a small, dense, positively charged nucleus.
• D. Protons and neutrons are evenly distributed throughout the atom.

Answer: (C)

Verified step by step guidance

1. Understand the context of Rutherford's gold foil experiment, which involved firing alpha particles at a thin sheet of gold foil to observe how they scattered.
2. Recall the expectations before the experiment: according to the plum pudding model, alpha particles were expected to pass through with minimal deflection because the positive charge was thought to be spread out evenly.
3. Analyze the actual observations: most alpha particles passed through the foil, but some were deflected at large angles, and a few even bounced back.
4. Interpret these observations to conclude that the atom must have a small, dense, positively charged center that repels the positively charged alpha particles, which is the nucleus.
5. Summarize the major discovery: Rutherford concluded that atoms are mostly empty space with a tiny, dense nucleus containing the positive charge, disproving the idea that atoms are indivisible solid spheres or that positive charge is evenly distributed.