Q50 / 150 · MHT CET 2026 (20 April Shift 1) · Chemistry
Calculate the radius of atom of metal forming fcc unit cell having edge length $360$ pm
- A$180.04$ pm
- Correct answerB$127.26$ pm
- C$155.91$ pm
- D$254.67$ pm
Solution
For a face-centered cubic (fcc) unit cell, the atoms touch each other along the face diagonal.
The relationship between the edge length $a$ and the atomic radius $r$ is given by:
$\sqrt{2}a = 4r$
$r = \dfrac{a}{2\sqrt{2}}$
Given $a = 360$ pm:
$r = \dfrac{360}{2\sqrt{2}} = 90\sqrt{2}$
Using $\sqrt{2} = 1.414$:
$r = 90 \times 1.414 = 127.26$ pm
Answer: $127.26$ pm
The relationship between the edge length $a$ and the atomic radius $r$ is given by:
$\sqrt{2}a = 4r$
$r = \dfrac{a}{2\sqrt{2}}$
Given $a = 360$ pm:
$r = \dfrac{360}{2\sqrt{2}} = 90\sqrt{2}$
Using $\sqrt{2} = 1.414$:
$r = 90 \times 1.414 = 127.26$ pm
Answer: $127.26$ pm
Hence, the correct answer is option: 'B'.