1a. Use the BornHaber cycle to calculate the lattice energy of CaO. Use data from Appendix II and Table 9.1 in the textbook, and the following information: subH for calcium is 178 kJ mol1; IE1 and IE2 for calcium are 590 kJ mol1 and 1145 kJ mol1, respectively; EA1 and EA2 for oxygen are 141 kJ mol1 and 744 kJ mol1, respectively.

1b. Using electronegativity differences, determine whether the bond formed between each pair of atoms is pure covalent, polar covalent, or ionic: Ca and N Mg and I N and O N and N