Place the following in order of increasing magnitude of lattice energy. CaO MgO SrS
A) MgO

Question

Place the following in order of increasing magnitude of lattice energy. CaO MgO SrS
A) MgO < CaO < SrS
B) SrS < MgO < CaO
C) SrS < CaO < MgO
D) CaO < MgO < SrS
E) CaO < SrS < MgO

Quizplus · Accepted Answer

Lattice energy is directly proportional to the charge of the ions and inversely proportional to the distance between them. Since all three compounds have metal cations with the same charge (+2) but different nonmetal anions with varying radii and charges, we can compare their lattice energies by looking at the size and charge of the anions. SrS has the largest anion and therefore the weakest lattice energy, while CaO has the smallest anion and the strongest lattice energy. Therefore, the order of increasing magnitude of lattice energy is SrS < CaO < MgO. Choice C is the only option that correctly reflects this order.

Place the Following in Order of Increasing Magnitude of Lattice