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

Copper crystallises in $fcc$ with a unit cell length of $361 \ pm$. What is the radius of copper atom? ............... $pm$

Nickel crystallises in a $fcc$ type of unit cell,with edge length $0.3524 \ nm$. Calculate the radius of nickel atom. (in $nm$)

The density of chromium metal is $7.2 \, g \, cm^{-3}$. If the edge length of the unit cell is $289 \, pm$, determine the type of unit cell (Simple Cubic, Body-Centered Cubic, or Face-Centered Cubic). [Atomic mass of $Cr = 52 \, a.m.u.$, $N_A = 6.02 \times 10^{23} \, mol^{-1}$]

In a $bcc$ lattice having the edge length of $200 \ pm$, the cation has the radius of $70 \ pm$. The radius ratio of $\frac{r^{+}}{r^{-}}$ is (Given, $\sqrt{2}=1.4, \sqrt{3}=1.7$ and $\sqrt{6}=2.4$ )

Niobium crystallises in a body-centred cubic $(bcc)$ structure. If the density is $8.55 \, g \, cm^{-3}$,calculate the atomic radius of niobium using its atomic mass $93 \, u$.