$Na$ and $Mg$ crystallise in $b.c.c.$ and $f.c.c.$ type crystals respectively. The number of atoms of $Na$ and $Mg$ present in the unit cell of their respective crystals is:

The $Ca^{2+}$ and $F^{-}$ ions are located in $CaF_2$ crystal,respectively,at face-centered cubic lattice points and in

What is the coordination number of a particle in $fcc$ structure?

The structure of $Na_2O$ crystal is

If $AgI$ crystallises in zinc blende structure with $I^{-}$ ions at lattice points,what fraction of tetrahedral voids is occupied by $Ag^{+}$ ions? ............ $\%$

$A$ compound of $A$ and $B$ crystallises in a cubic lattice in which $A$ atoms occupy the lattice points at the corners of the cube. The $B$ atoms occupy the centre of each face of the cube. The probable empirical formula of the compound is