[weinus]

The energy levels of the hydrogen atom are given by En=-me⁴/(32pi²E_oh_barn², and are independant of the orbital angular momentum quantum number l, yet the Aufbau principle clealry implies that the energies of s, p, and d orbitals are different.  Explain this apparent paradox and provide an example of experimental evidence that supports your conclusion.

[Yggdrasil]

How does the hydrogen atom differ from other types of atoms?

[weinus]

It has one electron? but how does this explain the paradox?  Does the proper answer involve shielding?

[Borek]

Does the proper answer involve shielding?

Yes.

[Yggdrasil]

Basically, in multi-electron systems, you need to account for electron-electron interactions, which adds another term onto the Hamiltonian of the system.  This extra term in the Hamiltonian breaks the degeneracy of states with different orbital angular momenta.