The edge length of the unit cell of Nacl crystal lattice is 552 pm. If ionic radius of sodium ion is 95. What is the ionic radius of chloride ion:
(a) 190 pm (b) 368 pm (c) 181 pm (d) 276 pm
Answer: (c) Distance between centres of Na+ and Cl-
rNa+ + rCl- = 276 pm or 95 + rCl- = 276 pm
or rCl- = 276 - 95 = 181 pm