Which of the following have the higher melting point?

Question

The lattice energy for sodium iodide is 700 kJ./mol, while that for calcium sulfide is 2775 kJ/mol. Which of these salts do you predict has the higher melting point? explain

Answer 1

Calcium sulfide. The "lattice energy" refers to how tightly the atoms are holding onto each other in the ionic compound. Since the calcium sulfide lattice has higher energy, it will take a higher temperature to melt it down.

Answer 2

See page 2 of the following site for explanation:

http://courses.cm.utexas.edu/clabrake/ch302/ch14-notes.pdf