If the radii of $Na^{+}$ and $Cl^{-}$ are $95 \, pm$ and $181 \, pm$ respectively, then the edge length of the $NaCl$ unit cell is equal to ...... $pm$.

Calculate the density of an element having molar mass $27 \ g \ mol^{-1}$ that forms $fcc$ unit cell. $[a^3 \cdot N_A = 38.5 \ cm^3 \ mol^{-1}]$ (in $g \ cm^{-3}$)

Calculate the number of unit cells in $1 \, g$ of $NaCl$ crystal,which crystallizes in an $fcc$ structure. (Molar mass of $NaCl = 58.5 \, g/mol$)

The cubic unit cell of a metal (molar mass $= 63.55 \ g \ mol^{-1}$) has an edge length of $362 \ pm$. Its density is $8.92 \ g \ cm^{-3}$. The type of unit cell is

For a crystal, the angle of diffraction $(2 \theta)$ is $90^{\circ}$ and the second order line has a $d$ value of $2.28 \ \text{Å}$. The wavelength (in $\text{Å}$) of $X$-rays used for Bragg's diffraction is

$CsCl$ crystallises in a cubic structure that has $Cl^{-}$ at each corner and $Cs^{+}$ at the centre of the unit cell. If $r_{Cs^{+}} = 1.69 \ \mathring{A}$ and $r_{Cl^{-}} = 1.81 \ \mathring{A}$,what is the value of the edge length of the cube in $\mathring{A}$?