16   7 This question is about ions. (a) Draw a dot‑and‑cross diagram of the ionic compound potassium chloride. Show outer shell electrons only. (1) (b) Deduce the order of increasing size of the ions: Br–, Ca2+, Cl–, K+ Justify your answer. (4) .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................................................... Turn over 17   (c) A saturated aqueous calcium hydroxide solution contains 17.3 g in 10.0 dm3 of solution. Under these conditions the calcium hydroxide is fully dissociated into ions. What is the concentration of the calcium ions in this solution, in mol dm–3 ? (1) A 0.0233 B 0.0303 C 0.0431 D 0.0597 (Total for Question 7 = 6 marks)