Question

If radii of Na+,Ca2+ ions and Cl-, O2- ions are assumed to be the same.If the lattice energy of NaCl is 'x' the lattice energy of CaO would be
a)x/2
b)2x
c)4x
d)x/4​

Answer 1

Explanation:

stay home stay safe

stay home stay safe

Answer 2

Explanation:

Lattice energy =−

r

2

q

1

q

2

Where q

1

and q

2

are charges on ions and r is the distance between them.

Since inter-ionic distances in CaO and NaCl are similar, (larger cation has smaller anion and vice-versa) therefore ris almost the same.

Therefore, lattice energy depends only on the charge. Since the magnitude of charge on Na

+

and Cl

−

ions is unity and that on Ca

2+

and O

2−

ions is 2 each, therefore, the lattice energy of CaO is four times the lattice energy of NaCl ie. 4U.

Hence, option D is correct.