1. General
   1. centre of periodic table
   2. more than one electron in outer energy shell
      1. compared to alkali metals
         1. higher density
         2. less reactive
         3. higher melting point
         4. react slower with water & oxygen
   3. reaction with dilute acid varied
      1. copper no reaction
      2. iron yes
   4. magnetic elements
      1. only
         1. iron
         2. cobalt
         3. nickel
   5. used in construction metals
      1. iron imparticularly
   6. catalysts in chemical industry
2. sodium hydroxide + metal compound ---> metal hydroxide
   1. precipitate colour = metal
   2. CuSO4 (aq) + 2NaOH (aq) ---> Cu(OH)2 (s) + Na2SO4(aq)
   3. copper sulphate + sodium hydroxide ---> copper (II) hydroxide + sodium sulphate
   4. Cu2+ (aq) + 2OH- (aq) ---> Cu(OH)2 (s)
      1. ionic equation
      2. spectator ions
         1. sulphate
         2. sodium
3. colours of compounds
   1. NB group1 compounds white
   2. multiple ions
      1. electron shell shapes
   3. copper
      1. blue
         1. copper (II) Cu2+
      2. green
   4. iron
      1. green
         1. iron (II) Fe2+
      2. brown
         1. iron (III) Fe 3+
   5. nickel
      1. green
         1. nickel (II) Ni2+