The ground state energy of hydrogen atom is 2.-13.6 eV. Hence, the energy of the electron of a doubly ionised lithium atom in its 1st orbit will be

Options

A. `-4.5 eV`
B. `-13.6eV`
C. `-40.8 eV`
D. `-122.4 eV `

Answer

D

Explanation

`- 122.4 eV`, since `E_n =- (13.6Z^2)/(n^2),` Z = 3 for He.