Answer:
(B) the energy required to break apart one mole of an ionic compound into its gaseous ions
Explanation:
Lattice energy is the energy that would be obtained from the formation of an ionic compound from its gaseous ions. Therefore, the reverse process that responds the question would be the energy required to break apart an ionic compound and convert its component atoms into gaseous ions.
Lattice energy provides a measure of the stability of an ionic compound. When the ions bind to form the crystalline structure, heat (energy) is released. To break the ionic compound into the ions that form it, it is necessary to provide an energy equal to that released when formed, i.e. the lattice energy.