Question

Which pair of compounds is listed in order of increasing (more exothermic) lattice energy? MgO < CsCl LiF < LiI v LiF < MgO CaO < BaCl2 NaCl < KCl Flag this Question

Answer 1

Hey there!:

Answer : LiF < MgO

Explanation

Lattice energy depends on the charge of the constituent ions. In MgO, the charge of cation and anion are +2 and -2 respectively.In LiF, the charge of cation and anion are +1 and -1. Similarly, if the electronegativity of the anion is higher, the higher will be the lattice energy. Also, an ionic compound with smaller cation size will have higher lattice energy.

Here, the correct order is,

LiF > LiI    

NaCl > KCl    

MgO > CsCl  

CaO > BaCl2

LiF < MgO

Hope this helps!