Group 2 The Alkali Metals

• What is the trend in reactivity of Group 2 down the group?

  Increases
• Why does reactivity increase down group 2?

  Atomic radius increases as the number of electron shells increases, the outer electrons are further from the nucleus. There’s an increase in shielding so the outer electrons and the positive nucleus experience a weaker electrostatic force of attraction and so it’s easier to lose an electron down the group.
• How does the solubility of Group 2 hydroxides change down the group?

  Increases
• What is the solubility of magnesium hydroxide?

  It’s sparingly soluble and a suspension in water
• What’s the solubility of calcium hydroxide?

  Sparingly soluble and used as limewater
• What’s the solubility of barium hydroxide?

  Dissolves in water o produce a strongly alkaline solution
• What’s the trend of solubility of Group 2 sulfates down the group?

  Decreases
• What is the sulfate test?

  1. Add 2cm^3 of the test solution (that contains sulfate ions)
  2. Add an equal volume of HCl to the test tube (eliminating any other ions present)
  3. Add a few drops of barium chloride solution into the test tube
  4. If sulfate ions are present, a white precipitate forms
• What is the use of magnesium hydroxide?

  This is also known as milk of magnesia, used in indigestion remedies to neutralise excess stomach acid which causes heart burn, indigestion and wind
• What are the use of calcium hydroxide?

  This is sometimes referred to as slaked lime, used to treat acidic soil as most plants have an optimum level of acidity or alkalinity in which they thrive
• What are the uses of calcium oxide/ carbonate?

  Removes sulfur dioxide by flue gas desulfurization

  CaO + 2$H_2O$+ SO2 + 1/2 $O_2$-> CaSO4/ CaSO3 +2$H_2O$
• What are the uses of barium sulfate?

  Used as a ‘barium meal’ to outline the gut in medical X-Rays, barium compounds are toxic but it’s safe to use as barium sulfate is insoluble, also used to test for the presence of sulfate ions
• What are the properties of Titanium?

  Strong, low density and has a high melting point also used in hip replacements
• What is the process of extracting titanium?

  Titanium oxide is reacted with chlorine and carbon to form titanium chloride, TiCl4 and carbon monoxide.

  The TiCl4 is reduced to titanium by a reaction with magnesium metal. TiCl4 is a liquid and has simple molecular covalent bonding so the electrons are shared+ there’s weak IMF’s between molecules so a low melting point
• What is the second equation for the extraction of titanium?

  $2Mg+$$TiCl_4\ \rightarrow\ Ti+$$2MgCl_2$
• What is the trend in atomic radius down group 2?

  Increases as there’s an extra electron shell added to each element down the group
• What is the trend of first ionisation energy down group 2?

  Decreases as each element down group 2 has an extra electron shell, meaning that the outer electrons are further away from the nucleus, reducing the nucleus’s attraction making it easier to remove outer electrons
• What is the trend in melting points down group 2?

  Decrease as they have metallic structures and down the group the meta ions are bigger, the larger the atomic radius the further away the delocalised electrons are from the positive nuclei, so it takes less energy to break the bonds
• What type of reaction occurs when group 2 metals react with water and what are the products made?

  - the reaction is redox

  - a metal hydroxide and hydrogen is produced
• What happens when magnesium reacts with STEAM?

  - the reaction is much faster

  - magnesium burns a bright white flame

  Magnesium oxide and hydrogen is formed
• What are the observations of group 2 metals reacting with water?

  - fizzing (more vigorous down the group)

  - the metal dissolving (faster down the group)

  - the solution heating up (more down the group)

  - white precipitate with CALCIUM