CAIE A Level Chemistry 9701 · Chemical bonding

Chemical bonding: explain question

Explain4 marksStandard

Magnesium oxide ( $\ce{MgO}$ ) has a melting point of 2852 °C, while sodium chloride ( $\ce{NaCl}$ ) has a melting point of 801 °C.

Explain, in terms of the ionic bonding present, why the melting point of magnesium oxide is much higher than that of sodium chloride.

How this question is marked

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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