Question

An element having a face-centered cubic structure has a density of $6.23gc{m}^{-3}$. The atomic mass of elements is $60$. The edge length of the unit cell is:

• A. $400pm$
• B. $300pm$
• C. $425pm$
• D. $370pm$

Answer 1

The correct option is A $400pm$

$a^3=\frac{z\times M}{N_A\times d}$

$=\frac{4\times 60}{6.023\times {10}^{23}\times 6.23}$

$\Rightarrow a^3=64\times {10}^{-24}c{m}^3$

$\Rightarrow a=(4\times {10}^{-8}\times {10}^{10})pm=400pm$