Question

Rank the following ionic compounds in order of increasing attraction between their ions: KBr, SrBr2, CsBr

Please give an explanation as to how you got your answer.

Answer 1

The increasing order of attractions between the ions of compounds : CsBr < KBr < SrBr2

It can be observed from their lattice energy values also.

CsBr ( 644 kJ mol^-1 ) , KBr ( 671 kJmol^-1 ) , SrBr2 ( 2046 kJmol^-1).

As the charge on Mⁿ⁺ increases there is a greater attractive force between the ions and lattice energies increase.

In addition, the decrease in size of Mⁿ⁺ with increasing charge increases the attractive force between the ions and also increases the lattice energy.