Group 7

• Group 7 elements are known as the halogens
• They are diatomic molecules meaning they are made up of chemical joined together pairs of atoms
• Group 7 elements:

  • Fluorine (F)
  • Chlorine (Cl)
  • Bromine (Br)
  • Iodine (I)
• Halogens

  • Poisonous
  • Reactive
  • Diatomic molecules
  • Form covalent bonds with other non-metals
• Diatomic molecules

  Two atom molecules formed by sharing electrons and forming covalent bonds
• Simple molecular structures

  Covalent compounds formed between halogens and other non-metals like hydrogen or carbon
• As you go down the halogen group

  Melting and boiling points increase, reactivity decreases
• Halides

  Ions formed when a halogen gains an electron, e.g. fluoride, chloride, bromide, iodide
• Displacement reactions

  More reactive halogens displace less reactive ones, e.g. chlorine displacing bromine
• Fluorine is a very reactive yellow gas
• Chlorine is a reactive pale green gas
• Bromine is a poisonous brown liquid
• Iodine is a grey solid that produces poisonous purple vapours
• More reactive halogens will always displace less reactive halogens