(a) An element has atomic mass 93`g*mol^(-1)` and density 11.5`g*cm^(-3)`. If the edge length of its unit cell is 300 pm, identify the type of unit cell.
(b) Write any two differences between amorphous solids and crystalline solids.

Explanation

(a) We know, `rho=(ZxxM)/(N_(A)xxa^(3))` Where, `rho` = density of the unit cell = `11.5g*cm^(-3)`, Z = no. of particles present in unit cell, M = atomic mass of the element = `93g*mol^(-1)`,
`N_(A)` = Avogadro's number = `6.022xx10^(23)`, a = edge length of the unit cell = 300pm = `300xx10^(-10)cm`.
Now, `Z=(rhoxxN_(A)xxa^(3))/M`
`=(11.5xx6.022xx10^(23)xx(300xx10^(-10))^(3))/93=2.010~~2`
So, the value of Z represents bcc unit cell.