JEE Main201912 Apr 2019Evening ShiftChemistrySolid StateActual
The ratio of number of atoms present in a simple cubic, body centered cubic and face centered cubic structure are, respectively :
Options
- A4 : 2 : 1
- B1 : 2 : 4
- C4 : 2 : 3
- D8 : 1 : 6
Correct answer
B. 1 : 2 : 4
Step-by-step solution
Z SC   =   8   ×   1 8 =   1   [Atoms are only at the corners] Z BCC   =   8   ×   1 8   + 1 =   1   +   1 = 2 [Atoms are at the corners and at the body center] Z FCC   =   8   ×   1 8   +   6   ×   1 2 =   1   +   3   =   4 [Atoms are at the corners and at the face centers] Here, Z= effective number of atoms in the unit cell. Therefore, Z SC ​ :   Z B