Calculate the number of atoms present in a unit cell of an element having molar mass $190 \ g \ mol^{-1}$ and density $20 \ g \ cm^{-3}$. Given that $[a^3 \cdot N_A = 38 \ cm^3 \ mol^{-1}]$.

The density of $KBr$ crystal is $2.75 \, g/cm^3$ and the edge length of the unit cell is $654 \, pm$. Calculate the number of formula units per unit cell and identify the type of unit cell. $(K = 39 \, u, Br = 80 \, u)$.

$A$ binary compound $(A^{+} B^{-})$ has a rock salt structure. If the edge length is $400 \, pm$ and the radius of the cation $(A^{+})$ is $75 \, pm$, what is the radius of the anion $(B^{-})$ in $pm$?

Calculate the molar mass of a metal with density $1 \ g \ cm^{-3}$ forming a $bcc$ structure with an edge length of $420 \ pm$.

$Xe$ crystallizes in an $FCC$ structure. The edge length of its unit cell is $620 \, pm$. The radius of $Xe$ is $=$ ...... $pm$.

The edge length of a body-centered cubic $(BCC)$ unit cell is $390 \ pm$. If the radius of the cation is $150 \ pm$, what is the radius of the anion? (in $pm$)