Question

In the basic $CsCl$ crystal structure, $Cs ^{+}$ and $Cl ^{-}$ ions are arranged in a $bcc$ configuration as shown in the figure. The net electrostatic force exerted by the eight $Cs ^{+}$ ions on the $Cl ^{-}$ ions is

• A. $\frac{1}{4 \pi \varepsilon_{0}} \frac{4 e^{2}}{3 a^{2}}$
• B. $\frac{1}{4 \pi \varepsilon_{0}} \frac{16 e^{2}}{3 a^{2}}$
• C. $\frac{1}{4 \pi \varepsilon_{0}} \frac{32 e^{2}}{3 a^{2}}$
• D. zero

Answer 1

Answer: (D)

The electrostatic force due to one $Cs ^{+}$ ion is balanced by diagonally opposite other $Cs ^{+}$ ion. Thus, the net electrostatic force on $Cl ^{-}$ ion due to eight $Cs ^{+}$ ions is zero.