Question

The radii, $r_{N{a}^{+}}$ $=95$ pm and $r_{C{l}^{-}}$ $=181$ pm in NaCl (rock salt) structure. What is the shortest distance (in pm) between $N{a}^{+}$ ions?

• A. $778.3$
• B. $276.2$
• C. $195.7$
• D. $390.3$

Answer 1

The correct option is D $390.3$

a= $2(r_{N_a^{+}}+r_{C{l}^{-}})$

$a=2(95+181)=2\times 276=552pm$

shortest distance between ${Na}^{+}\&{Cl}^{-}=552/2=276pm$

shortest distance between $2{Na}^{+}$ ions $=\sqrt{(276{)}^2+(276{)}^2}$

$=390.32pm$