Atomic structure and alpha scatteringEdexcel International A Level Physics: Mind map

Exam questions on Atomic structure and alpha scattering

1. Copper has two stable forms of atom, copper-63 and copper-65. The nuclide notation for copper-63 is $^{63}_{29}\mathrm{Cu}$.
   Explain why atoms of copper-63 and copper-65 have the same chemical properties but different masses.2 marks
2. In 1909 Geiger and Marsden directed a narrow beam of alpha particles at a very thin gold foil inside an evacuated chamber. A detector was moved around the foil to count the alpha particles scattered through different angles.
   A very small number of alpha particles were scattered through angles greater than 90°. Explain what this shows about the structure of the atom.2 marks
3. In a repeat of the alpha particle scattering experiment, 2.4 × 10⁵ alpha particles are incident on a thin gold foil. About 1 in 8000 of the alpha particles is deflected through an angle greater than 90°. Before this experiment the plum pudding model proposed by J. J. Thomson was the accepted model of the atom.
   Calculate the number of alpha particles deflected through more than 90°, and state what the result shows about the size of the nucleus compared with the atom.3 marks