CAIE A Level Chemistry 9701 · Atomic structure
The first ionisation energies (in kJ mol) of the elements Na to Ar across Period 3 are: Na 496, Mg 738, Al 578, Si 787, P 1012, S 1000, Cl 1251, Ar 1520. Explain the pattern of first ionisation energies across Period 3, referring to the factors that influence ionisation energy.
4 marks, so the mark scheme is looking for about 4 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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