The table shows some properties of four Group VII elements. element melting point in °C boiling point in °C density of liquid at boiling point in g/cm³ colour chlorine −101 −35 light green bromine −7 3.12 red-brown iodine 114 184 4.93 grey-black astatine 302 337 6.35

1. (a)(i)Complete the table by estimating : the boiling point of bromine the density of liquid chlorine at its boiling point.[2]
2. (a)(ii)Use the information in the table to suggest the colour of astatine.[1]
3. (b)Explain why chlorine is used in water treatment.[1]
4. (c)Chlorine reacts with aqueous potassium iodide. The products are aqueous potassium chloride and aqueous iodine.
5. (c)(i)Construct the ionic equation for this reaction.[1]
6. (c)(ii)Explain why potassium chloride does not react with iodine.[1]
7. (d)Hydrated nickel(II) chloride has the formula NiCl2.xH2O. It has a relative formula mass of 238. Calculate the value of x in this formula. [The relative atomic mass of nickel, Ni, is 59] X = .......................................................................................... [2][2]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.