If the radius of 3rd orbit of hydrogen atom is 'x' then the radius of 4th orbit of `Li^(2+)` ion would be:

Options

A. `(27)/(16)x`
B. `(16)/(27)x`
C. `(9)/(16)x`
D. `(16)/(9)x`

Answer

B

Explanation

`r=(n^(2))/(Z)xx0.529`Ã…
`x=(9)/(1)xx0.529`Ã… . . .(i)
`r_(4)(Li^(2+))=(16)/(3)xx0.529`Ã… . . . . (ii)
Dividing eqns. (ii) by (i)
`(r_(4)(Li^(2+)))/(x)=(16)/(27)`
`r_(4)(Li^(2+))=(16xx x)/(27)`.