5.1.1. The atom
A subsection of Physics, 5054, through 5. Nuclear physics
Listing 10 of 23 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
View
Between 1909 and 1911, Geiger and Marsden carried out experiments in which alpha particles were fired at metal foil. Most of the alpha particles passed through the foil with small deflections, but some were deflected through a large angle. These results suggest that A atoms contain clouds of electrons through which some alpha particles cannot pass. B atoms contain neutrons that alpha particles bounce off. C atoms have positive and negative charges spread throughout their volume. D atoms have positive charges concentrated in a small volume.
5054_s05_qp_1
MCQ
2005
Paper 1, Variant 0
View
Questions Discovered
23