Question

the density of copper metal is 8.95 g cm-3

. If the radius of copper atom is 127.8 pm, is the copper unit

cell a simple cubic, a body-centred cubic or a face centred cubic structure?

(Given : At. mass of Cu = 63.54 g mol-1

and NA = 6.02 × 1023 mol-1

)​

Answer 1

Answer:

For fcc , Z = 4 , Atomic mass (M) = 63.554 , r = 127.8 pm , d = ? ?

Avogardo number NA=6.02×1023gmol−1

d=Z×Ma3×NA [∵ In Fc.c. structure 2–√ a = 4 r]

a=4×r2–√=4×127.81.414=361.52 pm

d=4×63.556.02×1023×(3.61×10−8)3

d=0.89×101=8.9gmcm−3

Hope it helps u !!