Thomson, Rutherford, and Bohr models (intro)
Structure of Atom (School Level) · Chemistry
Study notes
How did the gold-foil experiment disprove Thomson's model? Step 1: Thomson's model predicted alpha particles would pass through with tiny deflections (charge spread out). Step 2: Rutherford observed most passed through, but some bounced back at large angles. Step 3: Large-angle scattering needs a strong repulsion from a tiny, dense, positive centre. Step 4: Conclusion: positive charge is concentrated in a small nucleus, not spread out — Thomson's model was wrong.