CAIE A Level Chemistry 9701 · Group 2
The enthalpy change of solution, , of the group 2 hydroxides becomes more exothermic down the group from magnesium hydroxide to barium hydroxide. Explain this trend in terms of the relative magnitudes of the lattice energy and the enthalpy change of hydration of the ions.
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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