Calculate the distance between two parallel $(220)$ planes in a crystal with an edge length of $450 \, pm$. (in $pm$)

Calculate the number of unit cells in $0.9 \ g$ of a metal if it forms a $bcc$ structure. Given: $\rho \times a^3 = 3 \times 10^{-22} \ g$.

Calculate the volume of the unit cell for an element having a molar mass of $56 \ g \ mol^{-1}$ that forms $bcc$ unit cells. $\left[\rho \cdot N_{A} = 4.8 \times 10^{24} \ g \ cm^{-3} \ mol^{-1}\right]$

Calculate the molar mass of an element if it forms $fcc$ unit cell structure. [Mass of unit cell $= 1.8 \times 10^{-22} \ g$,$N_A = 6.022 \times 10^{23} \ mol^{-1}$]

The volume of a simple cubic unit cell is $x \times 10^{-23} \ cm^3$. Calculate the value of $x$ if the volume occupied by a particle in it is $2.1 \times 10^{-23} \ cm^3$.

Calculate the radius of an atom of an element in $pm$ if it forms $bcc$ unit cell structure having edge length $4.3 \times 10^{-8} \ cm$.