A doubly ionised lithium atom is hydrogen like with atomic number `Z=3` Find the wavelength of the radiation required to excite the electron in `Li^(2+)` from the first to the third Bohr orbit.

Answer

`113.74Å`

Explanation

`(1)/(lambda)=RZ^(2)[(1)/(n_(1)^(2))-(1)/(n_(2)^(2)]]=Rxx9[(1)/1^(2)-(1)/3^(2)]`
`(1)/(lambda)=8R`
`R=(1)/(8R)= 113.74Å`