The hydrogen -like species `Li^(2+)` is in a spherically symmetric state `S_(1)` with one node. Upon absorbing light , the ion undergoes transition to a state `S_(2)`. The state `S_(2)` has one radial node and its energy is equal is to the ground state energy of the hydrogen atom.
The sate `S_(1)` is

Options

A. 1 s
B. 2 s
C. `2p`
D. 3 s

Answer

B

Explanation

`s_(1)` is spherically symmetrically state, i.e. it correspond to a s-orbital. Also, it has one radial node.
Number of radial nodes `=n-l-1" "rArr" "n-0-1=1 " "rArr" "n=2` i.e `s_(1)=2s-` orbital.