CIE Nov 2017 v3 Paper 2 Q2

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The elements in the third period, and their compounds, show trends in their physical and chemical properties. (a) A sketch graph of the first ionisation energies of five successive elements in the third period is shown. PMT ionisation energy Mg Si Al atomic number (i) Explain why there is a general increase in the first ionisation energy across the third period.[2] (ii) Sketch, on the graph, the position of the ionisation energies of the two elements that come before Mg in this sequence. [2] (iii) Explain, with reference to electron arrangements, the decreases in first ionisation energy between Mg and Al and between P and S. Mg and AlP and S[4]UCLES 2017 9701/23/O/N/17 [Turn over<br /> PMT (b) The chlorides of the elements in the third period behave in different ways when added to water, depending on their structure and bonding. L and M are each a chloride of an element in Period 3. A student investigated L and M and their results are given. L is a white crystalline solid with a melting point of 987 K. L dissolves in water to form an approximately neutral solution. Addition of NaOH(aq) to an aqueous solution of L produces a white precipitate. M is a liquid with a boiling point of 331 K. M is hydrolysed rapidly by cold water to form a strongly acidic solution, a white solid and white fumes. Identify L and M. Explain any properties and observations described. Give equations where appropriate. (i) L is[3] (ii) M is[3] [Total: 14]UCLES 2017 9701/23/O/N/17<br />

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