Module 3- Group 2

• Valency


  The number of electrons an atom has to gain, lose or share to form a chemical bond
• Valency of Group 2…

  Is 2
• The elements react to lose 2 electrons, making a +2 ion
• Group 2 elements are oxidised from 0—> +2
• Mg (s) + 2HCl (aq) —> MgCl”2” (aq) + H”2” (g)


  Mg is oxidised from 0–> +2

  H is reduced from -1 —> 0
• All Group 2 hydroxides are alkaline, meaning they are known as the ’Alkaline Earth Metals’
• High Melting and Boiling Points

  • Held together by metallic bonding
  • electrostatic attraction between positive ions and delocalised electrons
  • lots of energy is required to overcome the strong metallic bonds
• Good Conductors of Electricity

  • Contain delocalised electrons which are free to move around the structure and carry charge
• Trends down the group

  1. Size of atoms and ions increase
  2. ionisation energy decreases
  3. reactivity increases