A metal crystallises in simple cubic lattice. The volume of one unit cell is $6.4 \times 10^7 \mathrm{pm}^3$. What is the radius of the metal atom in pm ?

An element occurs in the body centred cubic structure with edge length of 288 pm . The density of the element is $7.2 \mathrm{~g} \mathrm{~cm}^{-3}$. The number of atoms present in 208 g of the element is nearly

If AgCl is doped with $1 \times 10^{-4}$ mole percent of $\mathrm{CdCl}_2$ the number of cation vacancies (in $\mathrm{mol}^{-1}$ ) is

An element (atomic weight $=250 \mathrm{u}$ ) crystallises in a simple cubic lattice. If the density of the unit cell is $7.2 \mathrm{~g} \mathrm{~cm}^{-3}$. What is the radius (in $\mathop {\rm{A}}\limits^{\rm{o}}$ ) of the atom of the element?

$$ \left(N_A=6.02 \times 10^{23} \mathrm{~mol}^{-1}\right) $$