Group 2

• reactivity increases going down the group
• First Ionisaiton Energy decreases going down the group
• Melting point decreases going down the group
• Reactions of Ca, St and Ba with water (X):

  X + 2 H2O -> X(OH)2 + H2
• What group 2 element is used to extract Ti from TiCl4

  Magnesium
• Extraction of Ti:

  TiCl4 + 2 Mg -> Ti + 2 MgCl2

  • slow
  • dilute HCl is added to react excess Mg -> MgCl which dissolves in water
• Solubility of hydroxydies:

  solubility increases going down the group

  -> OH- concentration increases

  -> alkalinity increases
• How soluble is magnesium hydroxide?

  Mg(OH)2 is sparingly soluble
• What is the use of Mg(OH)2?

  in medicine to neutralise stomach acid
• What is the use of Ca(OH)2?

  in agriculture to treat acidic soil
• What is the use of CaO or CaCO3?

  in flue gas desulphurisation to remove SO2
• What is BaSO4 used for?

  in x-rays as insoluble but hihgly toxic
• What is Mg used for?

  to extract Ti form TiCl4