Aluminium crystallises in a cubic close-packed structuure. Its metallic radius is 125pm.
(i) What is the length of the side of the unit cell?
(ii) How many unit cells are there in `1.00cm^(3)` of aluminium? ?

Explanation

ccp structure in fcc type
For fcc :
`a = 2 sqrt(2 r) = 2 xx 1.414 xx 125 pm = 353.5 pm`
`= 354 pm`
Volume of one unit cell
`= (354 xx 10^(-10) cm)^(3) = 4.44 xx 10^(-23) cm^(2)`
Unit cell in 1 `cm^(3) = (1)/(4.44 xx 10^(-23))`
`= 2.25 xx 10^(22)`