$1.666 \times 10^{21}$

$3.333 \times 10^{21}$

$2.499 \times 10^{21}$

$4.833 \times 10^{21}$

$1.204 \times 10^{23}$

$1.823 \times 10^{23}$

$6.022 \times 10^{23}$

$3.011 \times 10^{23}$

It arises when a particle is missing from its regular site in the crystal lattice during crystallisation.

The vacancy defect can also be developed when the substance is heated.

In this the mass of substance decreases.

The density of crystal remains same when vacancy defect is created.

$1.5 \times 10^{-23} \mathrm{~cm}^3$

$2.9 \times 10^{-23} \mathrm{~cm}^3$

$2.1 \times 10^{-23} \mathrm{~cm}^3$

$3.7 \times 10^{-23} \mathrm{~cm}^3$