Lithium metal crystallizes in a body centred cubic crystal. If the length of the side of the unit cell of…
Lithium metal crystallizes in a body centred cubic crystal. If the length of the side of the unit cell of lithium is $351 \mathrm{pm}$, the atomic radius of lithium will be :
$300.5 \mathrm{pm}$
$240.8 \mathrm{pm}$
$151.8 \mathrm{pm}$
$75.5 \mathrm{pm}$
Solution
For bcc type of unit cell
$\begin{aligned}
\sqrt{3} \mathrm{a} & =4 \mathrm{r} \\
\mathrm{r} & =\frac{\sqrt{3}}{4} \mathrm{a} \\
& =\frac{1.732 \times 351}{4} \\
& =151.98
\end{aligned}$