Potassium crystallizes with a

If the distance between $Na^{+}$ and $Cl^{-}$ ions in $NaCl$ crystal is $a \, pm$, what is the length of the cell edge?

The number of equidistant oppositely charged ions in a sodium chloride crystal is

The number of hexagonal faces that are present in a truncated octahedron is

Which of the following expressions is correct in the case of a $CsCl$ unit cell (edge length '$a$')?

$A$ cubic solid is made up of two elements $X$ and $Y$. Atoms of $X$ are present on every alternate corner and one at the center of the cube. $Y$ is at $\frac{1}{3}$ of the total faces. The empirical formula of the compound is