For $bcc$ cubic coordination the value of radius ratio is

An element crystallizes in a structure such that the unit cell is a cube with one atom at each corner and two atoms on its body diagonal. If the volume of this unit cell is $24 \times 10^{-24} \, cm^3$ and the density of the element is $7.2 \, g \, cm^{-3}$,calculate the number of atoms present in $200 \, g$ of the element.

The number of carbon atoms per unit cell of diamond unit cell is

Which of the following statements is not true about the $NaCl$ structure?

The structure of $MgO$ is similar to $NaCl$. What would be the coordination number of magnesium?

An ionic compound has a unit cell consisting of $A$ ions at the corners of a cube and $B$ ions on the centres of the faces of the cube. The empirical formula for this compound would be