Group 2

• Atomic radius

  atomic radius increases as you go down the group because each extra shell is further away
• Melting point

  • melting point decreases as you go down the group
  • ion cores have a larger radius
  • so free electrons experience less attraction to the nucleus due to radius
  • so bonding is weaker so melting point is lower
• Reaction with water

  • G2 + water = metal hydroxides
  • reactivity increases as you go down the group
  • lower elements have a lower ionization energy
  • ( beryllium doesn't react with water because if it loses 2 electrons it becomes tiny and has a high charge density and turns unstable)
• Solubility of salts

  • solubility of hydroxides increase as you go down the group
  • solubility of sulfates decreases as you go down the group
  • (magnesium is insoluble + barium is insoluble)
• Ionization energy

  • ionization energy decreases as you go down the group as electrons are far away so experience less attraction to the nucleus
• Uses of group 2 metals - titanium extraction

  1. convert titanium oxide to titanium chloride using chlorine gas and carbon
  2. heat titanium chloride with magnesium metal at 1000 degrees
  3. ticl4 + 2mg = ti + 2mgcl2
• uses of group 2 metals - base to neutralize acids

  • calcium/magnesium hydroxides are used to neutralize acids
  • ca - neutralize acidic soils in agriculture
  • mg - in indigestion tablets as an antacid to neutralize excess stomach acid
• Magnesium

  2Mg (s) + O2 (g) → 2MgO (s)Mg (s) + H2O (g) → MgO (s) + H2 (g)