Calculate the radius ratio of `2^(nd)` excited state of `H & 1^(st)` excited state of `Li^(+2)`.

Explanation

`2^(nd)` excited state, means `e^(-)` is present in `3^(rd)` shell of hydrogen
`r_(3) = 0.529xx((3)^(2))/(1)=0.529xx9`
`1^(st)` excited state, means `e^(-)` exist in `2^(nd)` shell of `Li^(+2)`
`r_(2)=0.529xx((2)^(2))/(3)`
`=0.529xx(4)/(3)implies ((r_(3))_(H))/((r_(2))_(Li^(+2)))=(0.529xx(9)/(1))/(0.529xx(4)/(3))`
`=("radius of " 2^(nd) " excited state of hydrogen")/("radius of " 1^(st) " excited state of " Li^(+2)) implies ((r_(3))_(H))/((r_(2))_(Li^(+2)))=(27)/(4)`