What is the number of unit cells present in a cubic pack crystal lattice having 4 atoms per unit cell and weighing $$0.60 \mathrm{~g}$$ (molar mass $$\left.60 \mathrm{~g} \mathrm{~mol}^{-1}\right)$$ ?

Find the radius of an atom in fcc unit cell having edge length $$393 \mathrm{pm}$$.

Calculate the number of atoms present in unit cell of an element having molar mass $$190 \mathrm{~g} \mathrm{~mol}^{-1}$$ and density $$20 \mathrm{~g} \mathrm{~cm}^{-3}$$.

$$\left[\mathrm{a}^3 \cdot \mathrm{N}_{\mathrm{A}}=38 \mathrm{~cm}^3 \mathrm{~mol}^{-1}\right]$$

Which of the following characteristic properties is NOT true for crystalline solid?