Niobium crystallizes in a $bcc$ structure. If its density is $8.55 \, g/cm^3$, calculate the atomic radius of niobium. [Atomic mass of $Nb = 93 \, u$] (in $pm$)

An element (atomic mass $= 60$) has a face-centered cubic $(FCC)$ structure with a density of $6.23 \ g \ cm^{-3}$. The edge length of the unit cell is.... $(N_A = 6.02 \times 10^{23} \ mol^{-1})$

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

How many unit cells are present in $39 \ g$ of potassium that crystallizes in a body-centred cubic structure? $[At. \ wt. \ of \ K = 39]$

The number of atoms in $4.5 \ g$ of a face-centred cubic crystal with edge length $300 \ pm$ is (Given: Density $= 10 \ g \ cm^{-3}$ and $N_A = 6.022 \times 10^{23}$)

Which is the volume of unit cell of a metal (atomic mass $25 \ g \ mol^{-1}$) having $BCC$ structure and density $3 \ g \ cm^{-3}$?