Lithium has a $bcc$ structure. Its density is $530 \ kg \ m^{-3}$ and its atomic mass is $6.94 \ g \ mol^{-1}$. Calculate the edge length of a unit cell of lithium metal in $pm$ $(N_A = 6.02 \times 10^{23} \ mol^{-1})$.

What is the number of atoms in $1000 \ g$ of an $FCC$ crystal? Given density $= 10 \ g \ cm^{-3}$ and edge length $= 200 \ pm$.

Sodium metal crystallises in a body-centred cubic $(BCC)$ lattice with an edge length of $x \ \mathring{A}$. If the radius of the sodium atom is $1.86 \ \mathring{A}$, the value of $x$ is:

$A$ metal crystallizes in a $BCC$ structure. The edge length of its unit cell is $3.04 \ \mathring{A}$. What is the volume of its unit cell in $cm^3$?

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:

The diffraction pattern of a crystalline solid gave a peak at $2 \theta = 60^{\circ}$. What is the distance (in $cm$) between the layers which gave this peak? ($\lambda$ of $X$-rays is $1.54 \mathring{A}$) ($\sin 30^{\circ} = 0.5$,$\sin 60^{\circ} = 0.866$; $n = 1$)