How many unit cells are present in a $1.00 \ g$ cube of ideal $NaCl$ crystal?

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 $g \ cm^{-3}$)

Sodium metal crystallizes in a body-centered cubic $(BCC)$ lattice with a unit cell edge length of $4 \ \mathring{A}$. The radius of the sodium atom is $..... \times 10^{-1} \ \mathring{A}$ (Nearest integer).

Calculate the volume of a unit cell having four particles in it with a density of $19.0 \ g \ cm^{-3}$ [molar mass of element $= 190 \ g \ mol^{-1}$].

$CsBr$ has $bcc$ structure with edge length $4.3 \ \mathring{A}$. The shortest interionic distance in between $Cs^{+}$ and $Br^{-}$ (in $\mathring{A}$) is :

Copper crystallizes in an $fcc$ lattice with an edge length of $3.61 \times 10^{-8} \, cm$. If the measured density is $8.92 \, g \, cm^{-3}$,calculate the theoretical density of the crystal in $g \, cm^{-3}$. (Atomic mass of $Cu = 63.5 \, g \, mol^{-1}$)