How to find Cordination Number (NN) , NNN of FCC unit cell

What is common in HCP and FCC unit cell ?

The vacant space in FCC unit cell is

In sc, bcc and fcc the ratio of number of atoms per unit cell is given by

Total number of lattice points in SCC, BCC and FCC unit cell are respectively :-

Na and Mg crystallize in bcc- and fcc-type crystals, the ratio of number of atoms present in the unit cell of their respective crystal is

A metal 'M' is crystallised in F.C.C lattice. The number of unit cells in it having 2.4xx10^(-24) atoms

Assertion : The packing efficiency is maximum for the fcc structure. Reason : The cordination number is 12 in fcc structure.

A metal can be crystallized in both BCC and FCC unit cells whose edge lengths are 2 pm and 4 pm respectively. Then ratio of densities of FCC and BCC unit cells is