Al (at. wt 27) crystallizes in the cubic system with a cell edge of `4.05A^(@)`. Its density is `2.7gcm^(-3)`. Determine the unit cell type and calculate the radius of the Al atom

Options

A. fcc, 2.432 Å
B. bcc, 2.432 Å
C. bcc, 1.432 Å
D. fcc, 1.432 Å

Answer

D

Explanation

`rho=(zxxM)/(N_(0)xxa^(3)),2.7=(zxx27)/(6.02xx10^(23)xx(4.05)^(3)xx10^(-24))therefore z=4`
Hence it is face centred cubic unit lattice. Again `4r=asqrt(2)=5.727`Å `therefore r=1.432` Å