Question

An element having an atomic radius of 0.14 nm crystallizes in an fcc unit cell. What is the length of a side of the cell?

Options

• 0.56 nm

• 0.24 nm

• 0.96 nm

• 0.4 nm

Answer 1

0.4 nm

Explanation:

For an fcc unit cell

r = ${\displaystyle \frac{\sqrt{2}\text{a}}{4}}$

a = ${\displaystyle \frac{4\text{r}}{\sqrt{2}}}$

= ${\displaystyle 2\sqrt{2}\times 0.14}$

= 0.39

≈ 0.4 nm