Group 2

• Elements in group 2:

  All alkaline earth metals so all bond metallically and are solid at room temperature
• Down a group of metals:

  Cations are bigger so melting point decrease
• Extraction of titanium using Mg:

  1. First heated with C & Cl which form titanium chloride TiO2 + 2Cl2 + 2C =TiCl4 +2CO
  2. Then is reduced by Mg TiCl4 + 2Mg = Ti + 2MgCl2
• Acid Rain:

  Results form burning fossil fuels, sulfur dioxide reacts with oxygen to form sulfur trioxides which causes acid rain (2SO2 + O2 = 2SO3)
• Using calcium to prevent H2SO4:

  CaO (quicklime) + H2O = Slurry

  Spray slurry over SO2

  = CaSO3 (can be reused)

  CaCO3 (limestone) + H2O = slurry

  Spray slurry over SO2

  = CaSO3 + CO2
• Reaction with water:

  Form hydroxide

  speed of reaction increases down the group

  Beryllium doesnt react at room tem
• Solubility increase.. hydroxides

  down a group
• Mg Hydroxide can be used to

  Cure heartburn because not too strong (low solubility)
• Using CaOH to neutralise soil:

  Strong and readily available base
• Down a group solubility of sulphates:

  Decreases
• Using Barium sulphate in X-rays:

  Br is toxic and dense

  BrSO is insoluble so can be digested and not absorbed (barium meal)
• Using barium chloride to detect sulfate ions:

  White precipitate will form because its insoluble
• Mg OH can be used to cure heartburn because

  Its a strong enough base to neutralise pH of stomach

  Its really low solubility in water mean its not strong enough to damage the body
• Atomic radius and ionisation energy

  Atomic radius increase down a group

  First IE decrease down a group
• The bigger the cation the

  Lower the melting point because there is a greater distance between the nuclei and delocalised electrons
• Down group 2 metallic bonding

  gets weaker (less attraction between cation and delocalised electrons)
• Mg has the lowest melting point
• Testing for sulfate ions

  Add BaCl2 to Na2SO4 to produce 2NaCl + BaSO4 which is insoluble indicating the presence of sulfate ions

  If NaCO3 is present then barium would react to form BaCO3 which is also a white precipitate

  To find the difference first add acid which breaks down carbonate ions to water and carbon dioxide
• Things that increase as you go down group 2

  Atomic radius

  Ionic radius

  Shielding of outer electron from the nucleus

  Nuclear charge
• Extracting iron form ores

  Heating it with carbon (not suitable for titanium because TiC forms which is too brittle)
• Mg reaction with steam

  Mg(s)+H2O(g)>MgO(s)+H2(g)
• Lime compounds formulas

  Limestone (CaCO3 s)

  Quick like (CaO s)

  Slaked lime (hydroxide) (Ca(OH)2 s)

  Lime water (Ca(OH)2 aq)
• Balanced equation for MgOH reacting with acid in stomach to cure heartburn

  Mg(OH)2(aq) + H2SO4(aq) > MgSO4(aq) + 2H2O(l)
• Hydrated lime

  Another name for calcium hydroxide