born haber cycles

• Endothermic steps: atomisation and ionisation 
• Exothermic steps: formation, lattice enthalpy
• • 1st electron affinities are exothermic 
  • The overall force between the atom and the incoming electron is attractive 
  • 2nd and higher electron affinities are endothermic
  • The overall between the anion and the incoming electron is repulsive 
• Born-Haber cycles cannot be used for any salt which contains polyatomic ions
• LE are always exothermic
• enthalpy of formation is exothermic
• atomisation is endothermic
• ionisation energies are endothermic
• exothermic reactions are represented with downwards arrows
• we first atomise the metal and then the non-metal, change state symbol to (g)
• label A = elements in their standard states

  label B = solid ionic compound

  label C = gaseous ions

  
• The second ionisation is always more endothermic than the first and so has a longer arrow