The edge length of fcc type unit cell of copper having atomic radius $127.6 \mathrm{pm}$ is equal to
The edge length of fcc type unit cell of copper having atomic radius $127.6 \mathrm{pm}$ is equal to
$295 \mathrm{pm}$
361 pm
$331 \mathrm{pm}$
$378 \mathrm{pm}$
Solution
For fcc type unit cell
$\mathrm{r}=\frac{\mathrm{a}}{2 \sqrt{2}} \quad \therefore \mathrm{a}=\mathrm{r}(2 \sqrt{2})=127.6(2 \sqrt{2})=360.85 \approx 361 \mathrm{pm}$