CAIE A Level Chemistry 9701 · Group 17
At 298 K and 1 atm pressure, chlorine is a gas, bromine is a liquid and iodine is a solid.
Suggest explanations for: (a) the trend in volatility of chlorine, bromine and iodine; (b) the trend in the strength of the covalent bond between the atoms in , and .
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.
Suggest means: Apply what you know to an unfamiliar situation. There may be more than one acceptable answer. Reason from the principle you have learned to the new context, and say which principle you are using.
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