Question on Thermochemistry

a) Using zinc chloride, ZnCl2, as an example, define lattice energy.

b) Using the data given below as well as relevant data from the Data Booklet, construct a Born-Haber energy level diagram for zinc chloride.
Electron affinity of chlorine = -346 kJmol-1
Enthalpy change of atomization of zinc = +131 kJmol-1
Enthalpy change of formation of ZnCl2(s) = -451 kJmol-1

Use the energy level diagram to calculate the lattice energy of zinc chloride

c) How would you expect the melting point of zinc chloride to compare with that of zinc bromide?
Explain your reasoning.

If you have the answer, you can post or email me at cambridgechemistry(NOSPAM)@yahoo.com.sg