The density of chromium metal is $7 \ g \ cm^{-3}$. If the edge length of the unit cell is $300 \ pm$, identify the type of unit cell. (Atomic mass of $Cr = 52$)

$KBr$ has a rock salt type structure and has a density of $3.70 \ g/cm^3$. The edge length of the unit cell is approximately [molecular weight of $KBr = 120 \ g/mol$]:

Tobacco seed globin forms face-centered cubic crystals with a unit cell dimension of $12.3 \, nm$ and a density of $1.287 \, g \, cm^{-3}$. Its molecular mass will be:

$NaCl$ has $4$ formula units per unit cell. If the edge length of the unit cell is $0.564 \, nm$,then the density of the crystal is ............ $\text{g/cm}^3$. $(NaCl = 58.5 \, \text{g/mol})$

$A$ metal $M$ crystallizes into two lattices: face-centered cubic $(fcc)$ and body-centered cubic $(bcc)$ with unit cell edge lengths of $2.0 \ \mathring{A}$ and $2.5 \ \mathring{A}$ respectively. The ratio of densities of the $fcc$ lattice to the $bcc$ lattice for the metal $M$ is $...........$ (Nearest integer).

Lithium metal crystallises in a body-centred cubic crystal. If the length of the side of the unit cell of lithium is $351 \ pm,$ the atomic radius of lithium will be $............$ $pm$.