Determine the number of atoms per unit cell in a body-centered cubic $(BCC)$ unit cell.

$A$ solid has a structure in which $W$ atoms are located at the corners of a cubic lattice,$O$ atoms at the centre of edges,and $Na$ atom at the centre of the cube. The formula for the compound is

The edge lengths of a simple cubic $(sc)$ and a face-centered cubic $(fcc)$ unit cell are equal. The ratio of the volume occupied by atoms in these two structures is .....

$A$ solid has a structure in which $W$ atoms are located at the corners of a cubic lattice,$O$ atoms are at the center of the edges,and $Na$ atoms are at the center of the cube. The formula for the compound is:

The coordination number of the point $B$ for a solid with the following structure is:

The coordination number of a metal crystallizing in a hexagonal close packed structure is