An element crystallises in a $fcc$ lattice with cell edge $250 \ pm$. Calculate the density of the element (atomic mass $= 90.3 \ g \ mol^{-1}$) (in $g \ cm^{-3}$)

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 $\sqrt{6}=2.4$ )

The density of $Li$ metal is $0.53 \ g/cm^3$ and the edge length of its unit cell is $3.5 \ \mathop A\limits^o$. Calculate the number of $Li$ atoms in the unit cell. $(N_A = 6.02 \times 10^{23} \ mol^{-1}, M = 6.94 \ g \ mol^{-1})$

In a body-centred cubic $(bcc)$ lattice of potassium,the correct relation between the atomic radius $(r)$ of potassium and the edge-length $(a)$ of the cube is:

If the density of a gold $(Au)$ crystal crystallizing in a $ccp$ structure is $19.3 \, g/cm^3$,what will be the radius of the atom? (Given: $Au = 197 \, amu$)

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 $Cr = 52$)