Which experimental evidence led to the development of the Rutherford atomic model from the previous plum pudding model?

• A. The oil drop experiment, which measured the charge of the electron
• B. The cathode ray experiment, which demonstrated the existence of electrons
• C. The gold foil experiment, which showed that atoms have a small, dense nucleus
• D. The discovery of isotopes through mass spectrometry

Answer: (C)

Verified step by step guidance

1. Recall the plum pudding model proposed by J.J. Thomson, which described the atom as a diffuse cloud of positive charge with negatively charged electrons embedded within it.
2. Understand that the gold foil experiment, conducted by Ernest Rutherford, involved firing alpha particles at a thin sheet of gold foil and observing their scattering patterns.
3. Note that most alpha particles passed through the foil with little deflection, but a small fraction were deflected at large angles, and some even bounced back.
4. Interpret this unexpected scattering as evidence that the positive charge and most of the atom's mass are concentrated in a very small, dense region called the nucleus, rather than spread out as in the plum pudding model.
5. Conclude that this experimental evidence led Rutherford to propose a new atomic model with a central nucleus, replacing the plum pudding model.