What is the atomic radius of an element if it crystallises in a $BCC$ structure with an edge length of unit cell $287 \ pm$ (in $pm$)?

Gold has a cubic close-packed structure which can be viewed as spheres occupying $74\%$ of the total volume. What is the edge length of the unit cell if the density of gold is $19.3 \ g/cm^3$? $(Au = 197 \ amu)$

$NH_4Cl$ crystallizes in a $bcc$ lattice. If the edge length of the unit cell is $387 \, pm$, the distance between oppositely charged ions is ........ $pm$.

An element $A$ has a face-centred cubic $(fcc)$ structure with an edge length equal to $361 \ pm$. The radius of atom $A$ is ............... $pm$.

Calculate the molar mass of an element having density $5.6 \ g \ cm^{-3}$ that forms a $bcc$ structure. $\left[a^3 \times N_{A}=75 \ cm^3 \ mol^{-1}\right]$

Calculate the volume of $fcc$ unit cell if the radius of a particle in it is $106.05 \ pm$.