Question

Na and Mg crystallize in BCC and FCC type crystals. The ratio of no. of atoms present in the unit cells of their respective crystals is:

• A. 1:1
  
• B. 1:2
  
• C. 2:1
• D. 1:4

Answer 1

The correct option is B 1:2


For BCC, $Z_{eff}$ = 2/unit cell

For FCC, $Z_{eff}$ = 4/unit cell

$\therefore$ Ratio = $\frac{2}{4}=1:2$