Copper has the fcc crystal structure. Assuming an atomic radius of 130 pm for copper atom (Cu = 63.54):the density of Cu is

As we knowρ=n×MmNA×a3(a) For fcc structure4r=2aa=22r=22×130pm=367.64pm=3.67×10−8cm(b) Volume of unit cella3=3.67×10−83cm3=49.43×10−24cm3(c) n = 4(d) ρ=4×63.546.023×1023×3.67×10−8cm3=8.54g/cm3