5. Nuclear physics
A section of Physics, 5054
Listing 10 of 279 questions
A student makes a model of an atom. The model contains 24 electrons, 25 protons and 26 neutrons. Some of these particles are inside a nucleus at the centre of the model. Determine the nucleon number (mass number) of the atom. Explain why the model represents a charged atom. The student makes a new model of a different isotope of the same element. Describe the nucleus of this new model. Americium-241 is radioactive. Its nuclide notation is 241 94Am. Determine the number of neutrons in a nucleus of americium-241. number = A nucleus of americium-241 emits an α-particle and decays to uranium-237. Complete the nuclear equation for the decay of americium-241. 94 Am → α + U Geiger and Marsden studied the structure of gold atoms. shows a version of their apparatus. Alpha-particles strike a thin gold foil. gold foil alpha-particle source slit detecting screen The apparatus shown is in a container from which all the air is removed. Suggest why it is necessary to remove all the air from the container. The alpha-particles are emitted from the source at random. Explain why most of the alpha particles from the source do not reach the gold foil. shows a model of an atom of the gold foil, with its nucleus at the centre. nucleus alpha-particle A alpha-particle B (not to scale) The alpha-particle labelled A is deflected by the nucleus, as shown. On , complete the path of the alpha-particle labelled B. Explain how the alpha-particle scattering experiment provides evidence for the existence of a small nucleus inside the atom.
5054_s15_qp_21
THEORY
2015
Paper 2, Variant 1
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Questions Discovered
279