Group 7 & 0

• Group 7

  • Fluorine is a reactive and dangerous poisonous gas
  • Chlorine is a less reactive poisonous green gas
  • Bromine is a volatile red liquid that is also posionous
  • Iodine is a dark grey solid that can form poisonous purple vapours (but can also be a life saving antiseptic)
• The Halogens exist as diatomic molecules (pairs of atoms) as they share molecules to form a covalent bond.
• Halogen can form covalent bonds with other non-metals. These compounds are known as simple molecular structures.
• Group 7 becomes less reactive as you go down the group.
• Group 7's melting and boiling points increase as you go down the group.
• Group 7 becomes less reactive as you go down the group because the nucleus has less power to pull away an electron from another atom. If the halogen can't attract another electron then it can't react.
• When a halogen forms an ionic bond with a metal it becomes a halide. They often form these with Alkali Metals.
• Displacement reactions

  • Involves a more reactive halogen displacing a less reactive one
  • For example : Chlorine + Potassium Bromide ---> Potassium Chloride + Bromine
• Noble gasses

  • Colourless gases
  • Unreactive (inert)
  • Exist as single atoms
  • Non-Flammable
  • Boiling point increases as you go down the group