In a face-centred cubic $(FCC)$ unit cell,what is the contribution of an atom located at the face to the unit cell?

The number of close neighbours in a body-centred cubic $(BCC)$ lattice of identical spheres is:

What is the total number of atoms present in an $fcc$ unit cell?

$A$ compound $M_pX_q$ has a cubic close packing $(ccp)$ arrangement of $X$. Its unit cell structure is shown below. The empirical formula of the compound is

An ionic compound has unit cells 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 of this compound is

$NaCl$ is a $FCC$ lattice where $Na^{+}$ ions are at corner and face centre positions. Chloride ions are at edge centres and body centre positions. How many $NaCl$ formula units will be in a unit cell?