## Chemistry: Molecular Approach (4th Edition)

order is $LiBr$ < $KI$ < $CaO$
$LiBr$ and $KI$ have low lattice energy because magnitude of charge on ions is 1. $CaO$ has higher lattice energy because magnitude of charge on ions is 2. Among $LiBr$ and $KI$, $LiBr$ has lower lattice energy due to large size of $Br$ compared to $Li$. So, order is $LiBr$ < $KI$ < $CaO$