Final answer:
MgO has a higher coulombic energy than NaF.
Step-by-step explanation:
The lattice energy of a compound depends on the product of the charges of the ions. In this case, NaF contains Na+ and F- ions, whereas MgO contains Mg2+ and O2- ions. The lattice energy of NaF is 910 kJ/mol, whereas the lattice energy of MgO is 3795 kJ/mol. Therefore, MgO has a higher coulombic energy than NaF.