At $T \ K$,copper (atomic mass $= 63.5 \ u$) has $fcc$ unit cell structure with edge length of $x \ \mathring{A}$. What is the approximate density of $Cu$ in $g \ cm^{-3}$ at that temperature? $(N_A = 6.0 \times 10^{23} \ mol^{-1})$

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 $pm$ $(N_A = 6.02 \times 10^{23} \ mol^{-1})$.

Sodium metal crystallizes in a $bcc$ lattice with a unit cell edge length of $a = 4.29 \ \mathring{A}$. What is the radius of the sodium atom in $\mathring{A}$?

Identify the instrument used to determine the crystal structure from the following:

$A$ certain element crystallises in a $bcc$ lattice of unit cell edge length $27 \mathring{A}$. If the same element under the same conditions crystallises in the $fcc$ lattice,the edge length of the unit cell in $\mathring{A}$ will be .........
(Round off to the Nearest Integer).
[Assume each lattice point has a single atom]
[Assume $\sqrt{3}=1.73, \sqrt{2}=1.41$]

Ferrous oxide has a cubic structure and each edge of the unit cell is $5.0 \, \mathring{A}$. Assuming the density of the oxide is $4.0 \, g \, cm^{-3}$,the number of $Fe^{2+}$ and $O^{2-}$ ions present in each unit cell will be ($M_w$ of $FeO = 72$)