Question

The atomic radius of metal crystallizing in fcc structure true is $1.25A^o$. Hence the volume occupied by atoms in cell crystal is:

• A. $4.078\times {10}^{-22}c{m}^3$
• B. $6.09\times {10}^{-23}c{m}^3$
• C. $3.27\times {10}^{-23}c{m}^3$
• D. $2.68\times {10}^{-22}c{m}^3$

Answer 1

The correct option is A $4.078\times {10}^{-22}c{m}^3$

For $FCC$ unit cell

$4r=\sqrt{2}\times a$ or $a=2\sqrt{2}\times r=3.5A^o$

Volume $=a^3=(3.5\times {10}^{-10}{)}^3=4.078\times {10}^{-22}c{m}^3$