theoretical and experimental values

• a perfectly ionic model

  ions are perfectly spherical

  charge is evenly distributed
• is theoretical and experimental values don't match this means that there is more covalent character
• the more polarisation the more covalent character there will be
• Explain why there is a significant difference in the lattice energy values for magnesium iodide.

  magnesium ion is small and highly charged

  iodide ion has a large ionic radius

  iodide ion is polarised by the magnesium ion

  therefore the bonding in magnesium iodide has covalent character

  
• Comment on the theoretical and experimental lattice energy values, giving the reasons for any differences and similarities.

  lithium chloride has similar theoretical and experimental lattice energy

  magnesium iodide has different theoretical and experimental lattice energy

  magnesium has a higher charge that lithium

  magnesium has a more polarising power than lithium

  iodide ion is larger than chloride ion and therefore is polarised more