This question is about the nuclear structure of the

1. This question is about the nuclear structure of the atom and atomic energy levels.
When the electron was first discovered it led to the idea that an atom consists of a lump of
positive charge in which the electrons are embedded.
In 1912 Geiger and Marsden carried out an experiment to test the validity of this idea. The
results of their experiment in fact suggested that the atom is mostly empty space with an
electrically charged nucleus of relatively large mass occupying only a small amount of space.
(This is the so-called nuclear model of the atom). Their experiment involved “firing” alpha
particles at a thin sheet of gold foil.
(a) State the nature of an alpha particle.
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(1)
The diagram below shows a small part of the gold foil with two alpha particles A and B
approaching the foil.
(b) (i) Some alpha particle trajectories lead to the idea that most of the atom is empty
space. On the diagram, draw such a trajectory for the alpha particle A.
(ii) Some other alpha particle trajectories lead to the idea that the atom has an
electrically charged, relatively massive nucleus. On the diagram, draw such a
A
B
gold foil
(1)