[zeoblade]

Why and how are orbitals said to be degenerate? I'm reading Housecroft's Inorganic Chemistry and I don't know how I've missed it but I have a feeling this is of some importance later on.

My understanding is that the electron's probability of being in a position degenerates with increasing distance from the nucleus, is this what degenerate orbitals are?

Then comes orbitals that are not degenerate such He, now I am a little confused. Would someone be kind to lead me with their rationale to an understanding of degenerate and non-degenerate orbitals?

[Borek]

http://en.wikipedia.org/wiki/Degenerate_energy_level

[zeoblade]

Thanks Borek, now my understanding is electrons in the same n quantum number are degenerate.

So does this mean 2s² electrons are degenerate because there are 2 electrons with opposing spin?

So that 2p⁴ have 2p^x as degenerate because 2 electrons fill the x-axis but 2p^y and 2p^z are only half filled and therefore not degenerate?

Or does it mean when there is more than one electron in the n=2 quantum, the whole shell is degenerate except for 2s¹?

[tamim83]

Actually, all electrons in the H atom that have the same n are degenerate.  So in hydrogen 2s and 2p electrons have the same energy.  For other atoms all electrons with the same n and l are degenerate.  So in oxygen for example the 2s electrons are lower in energy than the 2p electrons.  This is due to screening; the electrons shield or screen one another from the full charge of the nucleus.  s electrons spend more time near the nucleus on average than p electrons.  So not only do s electrons experience less shielding but they do the most shielding as well. 

Hope that helps some.