An element has a body-centred cubic (bbc) structure with a cell edge of 288 pm. The density of the element is `7.2g/cm^3`. How many atoms are present in 208 g of the element?

Explanation

z(b.c.c., lattice) = 2, a = 288 pm
`=2.88xx10^(-8)"pm"`
`d=7.2"g cm"^(-3),m=20g,n=?`
`d=(Zxxm)/(a^(3)xxn)`
`n=(Zxxm)/(a^(3)xxd)`
`=(2xx208g)/((2xx88xx10^(-8))"cm"^(3)xx7xx2"g cm"^(-3))`
`=(416xx10^(24))/(23.89xx7.2)=2.42xx10^(24)`