Halogens

• List three halogens

  • Chlorine
  • fluorine
  • iodine
  • astatine
• How many electrons do they have in their outer shell?

  8 electrons
• Describe how the reactivity changes as you go down the

  group

  They become less reactive, the atom becomes larger

  because there are more electron shells, further from the

  nucleus so the pull of the nucleus is less. So the electron

  is less likely to be gained as there is less of a positive pull.
• bromine + potassium iodide

  = Br2 + 2KI -> 2KBr + i2
• chlorine + sodium iodide

  = Cl2+ 2NaI -> 2NaCl + I2
• fluorine + potassium chloride

  = F2 + KCl -> 2KF + Cl2