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

Options

A. `1.208xx10^(24)`
B. `2.416xx10^(24)`
C. `1.208xx10^(31)`
D. `2.416xx10^(31)`

Answer

B

Explanation

Volume of the unit cell`=(288xx10^(-10))^(3)=23.9xx10^(-24)cm^(3)`
Volume of 208 g of the element`=(208)/(7.2)=28.88cm^(3)`
No. of unit cels in 28.88`cm^(3)=(28.88)/(23.9xx10^(-24))=12.08xx10^(23)` unit cells
Each bcc structure contains 2 atoms.
So, total atoms in `12.08xx10^(23)` unit cells`=2xx12.08xx10^(23)=24.16xx10^(23)=2.416xx10^(24)`.