group 2 alkaline earth metals and uses

?
View mindmap
  • Group 2 - alkali earth metals
    • trends
      • down the group
        • atomic radius increases
          • number of shells increase
            • more shielding form inner shells
              • less attraction between nucleus and e-
        • 1st IE decreases
          • atomic radius increases
            • more shielding
              • outer e- less attracted to nucleus so easier to remove
        • reactivity increases
          • 1st IE decreases
            • easier to react and form 2+ ions
          • reactions with water
            • water is the oxidising agent
            • 0 to +2
            • e.g. Sr(s) + 2H2O(l) ? Sr(OH)2(aq) + H2(g)
      • melting point generally decreases
        • atomic radius increases
          • attraction between ion and delocalised e- decreases
            • strength of metallic bonds decreases and so less energy needed to overcome
        • Mg is an exception
          • it has a different crystal structure
    • group 2 hydroxides
      • solubility increases down the group
        • Mg(OH)2 is sparingly soluble because they have low solubilities
    • group 2 sulphates
      • solubility decreases down the group
        • BaSO4 is insoluble and so is used in sulfate ion tests
    • uses
      • magnesium
        • reducing agent when extracting titanium from its ore (TiCl4)
          • TiO2 is converted to TiCl4 by heating with carbon nda stream of Cl2 gas. The TiCl4 is purified by fractional distillation before being reduced to Mg in a furnace
          • TiCl4(g) + 2Mg(l) ? Ti(s) + 2MgCl2(l)
      • medical
        • barium sulfate
          • opaque to X-rays
          • used in Barium meals
            • diagnose oesophagus, stomach or intestinal problems
        • magnesium hydroxide
          • used in indegestion tablets as an antacid to neutralise stomach acid
            • H+ + OH- -> H2O
      • calcium hydroxide
        • neutralises acidic soils
      • calcium carbonate or calcium oxide
        • removes suffer dioxide from flue gases
          • SO2 reacts with alkaline slurry to form CaSO3
            • E.g. CaO+ 2H O+ SO? CaSO + 2H O(s)2 (l)2(g) 3(s)2 (l)

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all group 2 resources »