Aluminium metal has a density of `2.72 g cm^(-3)` and crystallizes in a cubic lattice with an edge of `404 pm`. Which of the following is correct?

Options

A. It forms bcc unit cell
B. It forms fcc unit cell
C. Its `CN = 8`
D. Its `CN` is `6`

Answer

B

Explanation

`rho = Z_(eff xx Aw of Al)/(N_(a) xx a^(3)), Z_eff = ?`
`2.72 g cm^(-3) = (Z_(eff) xx 27)/(6.023 xx 10^(23) xx (404 xx 10^(-10))^(3)`
`:. Z_(eff) = 4`
Hence, it forms `fcc` structure with `CN = 12`.