Calculate the radius of an atom of a metal forming an $fcc$ unit cell having an edge length of $360 \text{ pm}$. (in $\text{ pm}$)

$A$ substance forms a face-centered cubic $(FCC)$ crystal. Its density is $1.984 \ g \ cm^{-3}$ and the edge length of the unit cell is $630 \ pm$. Calculate the molar mass of the substance in $g \ mol^{-1}$.

Potassium has a $bcc$ structure with a nearest neighbour distance of $4.52 \ \mathring{A}$. Its atomic weight is $39$. Its density (in $kg \ m^{-3}$) will be:

Copper (atomic mass $= 63.5$) crystallises in a $fcc$ lattice and has density $8.93 \, g \, cm^{-3}$. The radius of copper atom is closest to $.... \, pm$.

Calculate the edge length of a simple cubic unit cell if the radius of an atom is $167.3 \ pm$. (in $pm$)

Bragg's law is given by the equation