$A$ 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 $pm$?

Elements $A$ and $B$ have $fcc$ and $bcc$ structures respectively with a unit cell edge length of $3 \mathring{A}$ for both elements. The number of atoms in $210 \ g$ of $A$ is equal to the number of atoms in $594 \ g$ of $B$. If the density of $A$ is $7 \ g \ cm^{-3}$,what is the density of $B$ (in $g \ cm^{-3}$)?

Calculate the volume of a simple cubic unit cell if the radius of the particle in it is $400 \ pm$.

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

An element (atomic mass $= 100 \ g/mol$) having $bcc$ structure has a unit cell edge of $400 \ pm$. The density of the element is ................. $g/cm^3$.

If a metal crystallises in a face-centred cubic $(FCC)$ structure with a metallic radius of $25 \ pm$, the number of unit cells in $1.0 \ cm^3$ of the lattice is: