What did Rutherford's gold foil experiment demonstrate about the atomic nucleus?

• A. The nucleus contains only electrons.
• B. Electrons are evenly distributed throughout the atom.
• C. Atoms are mostly solid with no empty space.
• D. The nucleus is a small, dense, positively charged center within the atom.

Answer: (D)

Verified step by step guidance

1. Recall the setup of Rutherford's gold foil experiment: alpha particles were directed at a very thin sheet of gold foil to observe how they scattered.
2. Understand the key observation: most alpha particles passed straight through the foil, but some were deflected at large angles, and a few even bounced back.
3. Analyze what these observations imply about atomic structure: if atoms were solid or had evenly distributed positive charge, alpha particles would not pass through easily or be deflected so sharply.
4. Conclude that the atom must have a small, dense, positively charged center (the nucleus) that repels the positively charged alpha particles, causing the deflections.
5. Recognize that this experiment disproved earlier models suggesting electrons were evenly distributed or that atoms were solid, establishing the nuclear model of the atom.