group 2

• Atomic Radius


  Increases. Trend in atomic radius down the group. This trend is due to more orbitals and a weaker nuclear charge as the charge is offset by the shielding that has come about from more orbitals
• Density


  Increases. Trend in density down the group. Due to increased protons and neutrons within the nucleus of the elements
• First ionisation energy


  Decreases. Trend in first ionisation energies down the group. This is because the electrons get further from the nucleus so has a weaker pull from the nucleus
• Reactivity


  Increases. Trend in reactivity down the group. This is due to the electrons being further from the nucleus allowing the interaction with other molecules
• Melting point


  Decreases. Trend in melting point down the group. This is because the delocalised electrons are further from the nucleus as the atomic radius increases
• When an element from group 2 reacts with liquid water:


  X + 2H2O -> X(OH)2 + H2
• Reactivity with water down the group

  Increases. This is because the ionisation energy decreases so there are more molecules with enough energy for a successful reaction due to increased successful collisions
• Trend in solubility of hydroxides

  Increases going down the group. This is due to the increased pH which increases the OH- presence. The bond breaking becomes easier
• When a chlorate in group 2 reacts with sodium hydroxide:


  XCl2 + 2NaOH -> 2NaCl + X(OH)2HINT: Hydroxides
• Trend in solubility of sulphates going down the group


  Decreases
• Uses of Mg(OH)2


  Laxatives and Antacids
• Use of Ca(OH)2


  Neutralise Soil
• Pure Ti Extraction Equation

  TiCl4 + 2Mg -> Ti + 2MgCl2

  
• How long it takes for pure titanium to be extracted?

  2 - 3 days
• Temperature Required for Titanium Extraction


  1000 ℃
• The cooling period during titanium extraction


  7 days
• The type of reaction occurring during the extraction of titanium


  Redox
• How to test for sulphate ions


  BaCl2
• What colour precipitate is formed with the following reaction?BaCl2 + Na2SO4 -> 2NaCl + BaSO4

  White
• What do you add to the solution before adding BaCl2 to ensure that no CO2 is formed?

  HCl
• Uses of BaSO4, this is due to its insolubility, despite its toxicity


  X-Rays and GI Tract
• Equation for Wet Scrubbing with CaO


  CaO(s) + 2H2O(l) + SO2(g) -> CaSO3(s) + 2H2O(l)
• Equation for Wet Scrubbing with CaCO3


  CaCO3(s) + 2H2O(l) + SO2(g) -> CaSO3(s) + 2H2O(l) + CO2(g)