A substance A’ crystallizes in fee lattice.1. Calculate the number o

1.	A substance A’ crystallizes in fee lattice.1. Calculate the number of atoms present per unit cell of ‘A’.2. In a crystalline solid AB, some vacancy is produced by missing of equal number of oppositely charged ions. What is the defect called?
Answer» 1. The number of atoms present per unit cell of ‘A’. Contribution from 8 corners = 1/8 × 8 = 1 Contribution from centres of 6 faces = 1/2 × 6 = 3 Total number of atoms of A’ per unit cell = 1 +3 = 4 2. Schottky defect

A substance A’ crystallizes in fee lattice.1. Calculate the number of atoms present per unit cell of ‘A’.2. In a crystalline solid AB, some vacancy is produced by missing of equal number of oppositely charged ions. What is the defect called?

Answer»

1. The number of atoms present per unit cell of ‘A’.

2. Schottky defect