$AB$ crystallizes in a body-centred cubic $(bcc)$ lattice with edge length $a$ equal to $387 \ pm$. The distance between two oppositely charged ions in the lattice is ............... $pm$.

Calculate the density of a metal having a molar mass of $210 \ g \ mol^{-1}$ that forms a simple cubic unit cell. $(a^3 \cdot N_{A} = 21.5 \ cm^3 \ mol^{-1})$ (in $g \ cm^{-3}$)

Lithium has a $bcc$ structure. Its density is $530 \ kg \ m^{-3}$ and its atomic mass is $6.94 \ g \ mol^{-1}$. Calculate the edge length of a unit cell of lithium metal in $pm$ $(N_A = 6.02 \times 10^{23} \ mol^{-1})$.

In the Bragg's equation for diffraction of $X$-rays, $n$ represents:

The edge length of $fcc$ type unit cell of copper having atomic radius $127.6 \ pm$ is equal to (in $pm$)

An element crystallizes in an $fcc$ unit cell structure with an edge length of $200 \, pm$. If $200 \, g$ of the element contains $24 \times 10^{23}$ atoms, what is its density in $g/cm^3$?