Select the compound with the lowest lattice energy. A. CsBr(s)
B. NaCl(s)
C. SrO(5)
D. CaO(s)
E. KBr(s)

A. CsBr(s)

Explanation:

we will get here compound with the lowest lattice energy

solution

As we know that Lattice energy is always proportional to the charge of ions and it is inversely proportional to the size of ions.

so that by the smallest charge and the largest size give us the lowest lattice energy and that charge and size is express as here as

Charge

Cs (+1), K(+1), Na (+1), Cl(-1), Br(-1), Sr(+2), Ca(+2), O(-2)     1

and

Size

Na+ < Ca2+ < K+ < Sr2+ < Cs+, O2- < Cl- < Br-                2

so that here

correct answer is A. CsBr