CAIE A Level Chemistry 9701 · Atomic structure
A beam of protons, a beam of neutrons and a beam of electrons, all moving at the same velocity, are passed in turn through the same electric field.
Explain why the three beams behave differently in the electric field.
Explain also how the relative charges and relative masses of these particles give rise to the model of the atom in which a very small, dense nucleus contains the protons and neutrons and the electrons occupy shells in the empty space around the nucleus.
5 marks, so the mark scheme is looking for about 5 separate creditworthy points. Making the same point twice in different words earns it once.
Explain means: Give the reasons or the mechanism: why or how something happens. Link each point to the next with because, so or which means. A list of facts with no links usually loses the reasoning marks.
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