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.
Energy of the state `S_(1)` in units of the hydrogen atom ground state energy is

Options

A. `0.75`
B. `1.50`
C. `2.25`
D. `4.50`

Answer

C

Explanation

Ground state energy of electron in H-atom `(E_(H))`
`E_(H)=(kZ^(2))/(n^(2))=k(Z=1, n=1)," For "s_(1)" state of "Li^(2+)," "E=(k(3)^(2))/(2^(2))=(9)/(4)k=2.25k`