Explaining the trend in the reactivity of the halogens
2 marks · NormalState two trends that occur when you go down Group 7 (the halogens) in the Periodic Table.
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Also accept: Melting and boiling points increase; Colour gets darker; Physical state changes from gas to liquid to solid; Reactivity decreases
Common mistakes: Saying 'reactivity increases' (wrong way round); Incorrectly describing physical states
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Marking points
B1 · 1 mark · States one correct trend (e.g., colour darkens, melting/boiling point increases, or reactivity decreases)
B2 · 1 mark · States a second correct, different trend
Worked solution
Down Group 7: 1. The melting and boiling points increase. 2. The elements become less reactive. Other correct answers: the colour gets darker, and they change from gases to solids.