CAIE A Level Chemistry 9701 · The Periodic Table: chemical periodicity

The Periodic Table: chemical periodicity: compare question

Compare5 marksStandard

The table below shows some properties of two unknown elements, X and Y.

Property	X	Y
Melting point / °C	97.8	–101.5
Electrical conductivity of solid	good	poor
Reaction with water	vigorous reaction producing a gas that burns with a squeaky pop	no reaction
Nature of oxide formed	basic oxide, pH of aqueous solution = 12	acidic oxide, pH of aqueous solution = 3
Density / g cm⁻³	0.97	0.0032

Compare the likely positions of X and Y in the Periodic Table and suggest possible identities for each element.

How this question is marked

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.

Compare means: Give similarities or differences between two things, and say which side each point belongs to. Write each point as a pair, for example: A is X, whereas B is Y. Two separate descriptions rarely earn the marks.

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