Calculate the number of atoms present per unit cell if product of density and volume of unit cell is 1.8 10⁻²² ~g [Mass of an atom =4.5 10⁻²³ ~g ]

Step-by-step solution

The density of a unit cell relates atomic parameters through V = Z m , where V is volume, Z is atomic count per unit cell, and m is atomic mass. Given V = 1.8 10⁻²² g and m = 4.5 10⁻²³ g, we substitute into the relation: 1.8 10⁻²² = Z (4.5 10⁻²³) Solving for Z : Z = 1.8 10⁻²² 4.5 10⁻²³ = 1.8 4.5 10¹ = 0.4 10 = 4 The unit cell contains 4 atoms , corresponding to choice C .