Chemistry - Solid State Question with Solution | TestHub

The density of a unit cell is given by $d=\frac{Z\times m}{V}$, where $Z$ is the number of atoms per unit cell, $m$ is the mass of one atom, and $V$ is the volume of the unit cell.

Rearranging the formula, the mass of the unit cell is $d\times V=Z\times m$.

Given $d\times V=1.8\times 10^{-22}\text{ g}$ and $m=4.5\times 10^{-23}\text{ g}$.

Substituting the values:

$1.8\times 10^{-22}=Z\times 4.5\times 10^{-23}$

$Z=\frac{1.8\times 10^{-22}}{4.5\times 10^{-23}}$

$Z=\frac{18}{4.5}=4$

Answer: $4$