An element crystallizes in a $bcc$ lattice. The number of nearest neighbors of the element is

What is the coordination number of a particle in a simple cubic close-packed structure?

In a cubic structure,$W$ atoms are present at the corners of the unit cell,$O$ atoms are at the edge centers,and $Na$ atoms are at the center of the cube. What is the formula of the compound?

Which of the following is a $1:2$ type compound?

The empirical formula for a compound with a cubic close packed arrangement of anions and with cations occupying all the octahedral sites is $A_{x}B$. The value of $x$ is ..... .
(Integer answer)

The number of nearest neighbours and next nearest neighbours of an $Na^{+}$ ion in a crystal of $NaCl$ are respectively