C1 - Reactivity of Group 7

• What happens to the reactivity of the Halogens (group 7) as you go down the group?

  Reactivity decreases
• What happens to the melting & boiling points of the Halogens (group 7), as you go down the group?

  They increase
• Why does the reactivity of the Halogens (group 7) decrease as you go down the group?

  1. As you go down the group, atoms get larger
  2. So, the outer shell is further away from the nucleus
  3. So, the attraction between the outer shell electrons and the nucleus decreases/weakens
  4. So an outer shell electron is less easily gained
• What happens in a displacement reaction with halogens

  A more reactive halogen can displace a less reactive halogen from an aqueous solution
• What is the name of the group 7 elements?

  The halogens
• Colour changes for halogen displacement reactions:

  Halide salts (e.g. KCl, KBr) = colourless

  Bromine water = orange

  Chlorine water = colourless

  Iodine water = brown
• Why is it not correct to say that the boiling point of a single bromine molecule is 59°C?

  Boiling point is a bulk property