AS chemistry group 2

• Group II metals


  Lose two electrons to form 2+ ions when they react in order to achieve a full outer shell
• Atomic radius of group II metals

  • Increases down the group due to additional electron shells
• Reactivity of group II metals

  • Increases down the group due to increased electron shielding making the outer electrons easier to lose
• First ionisation energy of group II metals


  • Decreases down the group due to a greater atomic radius and increased amounts of shielding
• Melting point of group II elements


  • Decreases down the group as the larger ions within the metallic structure have weaker attractive forces acting over a greater distance
• Reaction of group II metals with water

  1. Metal is oxidised from OS 0 to OS +2

  2. Produces a metal hydroxide and hydrogen

  3. Metal hydroxide forms an alkaline solution
• Reaction of magnesium with water

  • Magnesium reacts slowly with liquid water
  • Reaction is faster with steam as it provides extra energy
  • Magnesium burns with a bright white flame to form hydrogen and magnesium oxide (a white powder)
• Solubility of group II hydroxides

  • Increases down the group, with magnesium hydroxide being the least soluble and barium hydroxide being the most soluble
• Uses of magnesium hydroxide

  • Used as an antacid in medicine to neutralise acids
  • Used in agriculture to neutralise acidic soils
• Solubility of group II sulfates

  • Decreases down the group, with magnesium sulfate being the most soluble and barium sulfate being the least soluble
• Use of barium sulfate


  • Used in medicine as barium meals, a form of medical tracer that allows internal tissues and organs to be imaged
  • Insoluble so cannot be absorbed into the bloodstream, making it safe to use
• Use of barium chloride

  Used as a test for sulfate ions, reacting to form a white precipitate of barium sulfate
• Magnesium used in the extraction of titanium


  Displacement reaction with titanium chloride
• Calcium oxide used in flue gas removal


  Reacts with sulfur dioxide to form calcium sulfite and water, removing sulfur dioxide from factory pollutants