1. Which of the following ionic compounds have the greatest lattice energy and hence highest melting/boiling point?1 pointNaFNaClMgOCaO

The lattice energy of an ionic compound is directly related to the charges on the ions and inversely related to the sizes of the ions. Therefore, the compound with the smallest ions and the highest charges will have the greatest lattice energy.

Here are the charges and sizes of the ions in the given compounds:

• NaF: Na+ (charge +1, larger size) and F- (charge -1, smaller size)
• NaCl: Na+ (charge +1, larger size) and Cl- (charge -1, larger size than F-)
• MgO: Mg2+ (charge +2, larger size than O2-) and O2- (charge -2, smaller size)
• CaO: Ca2+ (charge +2, larger size than Mg2+) and O2- (charge -2, smaller size)

Comparing these, we can see that MgO has the smallest ions and the highest charges, so it should have the greatest lattice energy and hence the highest melting/boiling point.