Question

A $fcc$ unit cell of aluminium contains how many atoms ?

• A. 1
• B. 2
• C. 3
• D. 4

Answer 1

Answer: (D)

$\frac{1}{8}\times 8$(at corners) $=1$
$\frac{1}{2}\times 6$ (at face centre)$=3$
$\therefore$ Total number of atoms $(z)=1+3=4$