CAIE A Level Chemistry 9701 · The Periodic Table: chemical periodicity
The electrical conductivities of the elements of Period 3 are not the same. Explain, in terms of structure and bonding, why the electrical conductivity of sodium is much greater than that of sulfur, and why the electrical conductivity of silicon is much less than that of sodium.
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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