Orbital energies in a hydrogen-like species

Besides providing information about the wave functions, solutions of the Schrodinger equation give orbital energies, E (energy levels), and equation 1.16 shows the dependence of E on the principal quantum number for hydrogen-like species.

For each value of n there is only one energy solution and for hydrogen-like species, all atomic orbitals with the same principal quantum number (e.g. 3s, 3p and 3d ) are degenerate.