In a body-centered cubic $(BCC)$ unit cell,the atom at the body center is shared by how many unit cells?

The vacant space in the $bcc$ unit cell is .............. $\%$

The coordination number of a metal crystallizing in a hexagonal close-packed $(hcp)$ structure 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.

In sodium chloride crystal,the number of next nearest neighbours of each $Na^{+}$ ion is

In a compound $AB$,$A$ atoms occupy the corners of the cube and the $B$ atoms occupy the body centre of the cube. If the $A$ atoms possess magnetic moment due to up-spin and $B$ atoms possess magnetic moment due to down-spin,the magnetic nature of the compound $AB$ in an isolated unit cell is