Group 2: The Alkaline Earth Metals

• In which group of the periodic table are alkaline earth metals found?

  Group 2
• How many electrons are in the outermost s-orbital of alkaline earth metals?

  Two electrons
• How do alkaline earth metals compare in reactivity to alkali metals?

  They are less reactive than alkali metals
• What is the appearance of alkaline earth metals?

  Shiny, silvery-white metals
• What happens to the atomic radius as you move down Group 2?

  The atomic radius increases
• Why does the atomic radius increase down Group 2?

  Each element has an extra electron shell
• What effect do inner electron shells have on outermost electrons?

  They shield outermost electrons from nucleus attraction
• What is the trend of first ionisation energy (IE₁) in Group 2?

  It decreases down the group
• What is first ionisation energy (IE₁)?

  Energy required to remove outermost electron
• Why does IE₁ decrease down Group 2?

  Increased distance and shielding from nucleus
• What is the first ionisation energy of beryllium (Be)?

  900 kJ/mol
• What is the first ionisation energy of magnesium (Mg)?

  738 kJ/mol
• What is the first ionisation energy of calcium (Ca)?

  590 kJ/mol
• Why does strontium (Sr) have a lower IE₁ than higher Group 2 metals?

  It has a larger atomic radius and shielding
• How does reactivity change as you move down Group 2?

  Reactivity increases down the group
• What happens to the melting points of Group 2 metals as you move down the group?

  Melting points generally decrease
• Why do larger atoms in Group 2 have lower melting points?

  Weaker attraction between cations and electrons
• Which Group 2 metal has a higher melting point than expected?

  Calcium (Ca)
• Why does calcium have a higher melting point than magnesium?

  It has a more efficient packing structure
• What is the reaction of calcium with cold water?

  Ca + 2H₂O → Ca(OH)₂ + H₂
• How does calcium's reactivity with water compare to magnesium?

  Calcium is more reactive than magnesium
• How does the solubility of Group 2 hydroxides change down the group?

  Solubility increases down the group
• Which Group 2 hydroxide is sparingly soluble?

  Mg(OH)₂
• Which Group 2 hydroxide is moderately soluble?

  Ca(OH)₂
• How does the solubility of Group 2 sulphates change down the group?

  Solubility decreases down the group
• Which Group 2 sulphate is highly soluble in water?

  MgSO₄
• Which Group 2 sulphate is sparingly soluble in water?

  CaSO₄
• Which Group 2 sulphates are practically insoluble in water?

  SrSO₄ and BaSO₄
• How can you identify sulphate ions in an unknown solution?

  Add barium chloride and sulphuric acid
• What indicates the presence of sulphate ions in a solution?

  Appearance of a white precipitate
• Why is barium sulphate (BaSO₄) used in identifying sulphate ions?

  It is remarkably insoluble in water
• What is a common use of barium compounds in medicine?

  Medical imaging with barium meals
• How does BaSO₄ help in X-ray imaging?

  It absorbs X-rays effectively
• What conditions can barium meals help diagnose?

  Blockages, tumours, and abnormalities
• Why is BaSO₄ highly insoluble in water?

  It does not dissolve in bodily fluids
• What is the Kroll process used for?

  Extracting titanium from its ore
• What is titanium tetrachloride (TiCl₄) used for in the Kroll process?

  It is reduced to titanium metal
• What is the first step in the Kroll process?

  Convert TiO₂ into TiCl₄
• What is the role of magnesium in the Kroll process?

  It acts as the reducing agent
• What is the reaction of calcium carbonate with sulphur dioxide?

  CaCO₃ + SO₂ → CaSO₃ + CO₂