What is degenerate orbital? How do you determine it?

[sangria1986]

Help!

I always thought i knew what degeneracy meant since gen chem in Hs. But now i'm confused. Zumdahl text says degenerate electron is if they have same energy. And electrons are said to be degenerate ( have same energy) if they are found in same principle number n. Thus electrons w say n= 2 are all the same.

Then elsewhere I see that the ionization energy to remove an electron from 2p orbital is much lower in 2p than 2s
because it says p orbitals are at lower energy. What am I missing here?

Also I read that ionization energy of electron is equal to orbital energy it is from. But this doesn't make sense to me because orbital energy should be highest at the outside-but removal of outer electrons have lowest ionization energy. Everything I get is from zumdahl so it's nt like they'd make typos right? What am I missing.

Also I know there are variations in ionization energies across the table-do we have to know this or just that the energy increases right to left and decreases top to bottom. ?

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[Rabolisk]

I too used Zumdahl text, although I sold it and no longer have it. p orbitals have higher energy than s orbitals, not lower. Ionization energy is defined as the energy input needed to remove an electron. So a higher orbital energy corresponds to lower ionization energy. One source of confusion is the sign convention. Often times the electron binding energy is given as a negative value (like electrostatic potential). In this case, the more negative value has higher magnitude or absolute value, and corresponds to higher ionization energy.

 

[sangria1986]

I too used Zumdahl text, although I sold it and no longer have it. p orbitals have higher energy than s orbitals, not lower. Ionization energy is defined as the energy input needed to remove an electron. So a higher orbital energy corresponds to lower ionization energy. One source of confusion is the sign convention. Often times the electron binding energy is given as a negative value (like electrostatic potential). In this case, the more negative value has higher magnitude or absolute value, and corresponds to higher ionization energy.

But in the text it says that p rbitals have deshielding allowing the electrons to be removed easier.

Also. What is degenerate then? all n are same or only electrons within s and within p?

Also what is an orbital? Shell? Subshell?

 

[sangria1986]

Also. Ionization energy is energy to Remove an electron. So the energy is always positive. But affinity is negative.

 

[Rabolisk]

P orbitals do have deshielding, and thus higher orbital energy, and lower ionization energy. All 2p orbitals are degenerate because they are equivalent. 2p orbitals and 2s orbitals are not degenerate.

An orbital is a function describing the position of an electron. Less technically, you would say hydrogen has a 1s orbital. Shell describes the principal quantum number, n, or 1, in the case of hydrogen. Subshell is the azimuthal quantum number, l, or s, in the case of hydrogen. There is one orbital in an s subshell of any shell, and there are always two electrons per shell. Likewise, there are three orbitals in a p subshell of any shell, and there are six total electrons in the p subshell.

 

[sangria1986]

P orbitals do have deshielding, and thus higher orbital energy, and lower ionization energy. All 2p orbitals are degenerate because they are equivalent. 2p orbitals and 2s orbitals are not degenerate.

An orbital is a function describing the position of an electron. Less technically, you would say hydrogen has a 1s orbital. Shell describes the principal quantum number, n, or 1, in the case of hydrogen. Subshell is the azimuthal quantum number, l, or s, in the case of hydrogen. There is one orbital in an s subshell of any shell, and there are always two electrons per shell. Likewise, there are three orbitals in a p subshell of any shell, and there are six total electrons in the p subshell.

in this statement did you mean 2 electrons per subshell? Otherwise im confused. Also basically subshell equals orbital?

 

[Rabolisk]

Sorry, I meant 2 electrons per orbital. Subshells aren't orbitals. There are three orbitals in a p subshell, and 5 in a d subshell.

 

[sangria1986]

Sorry, I meant 2 electrons per orbital. Subshells aren't orbitals. There are three orbitals in a p subshell, and 5 in a d subshell.

Thanks...I really appreciate this. So basically to review everything:

principle quantum is n. The l values determine degenercy. Orbitals with same n and l are degenerate.

The subshells are the l values- s p d f. Within each subshell are orbitals. Orbitals can only have 2 electrons. orbitals are probabilistic models that indicate a high chance of finding an electron.

if n =2 then there are a total of 8 electrons possible : s subshell-2 electrons, p subhsell-3 orbitals with 6 electrons, 2+6=8.

so if n=2, l=0->n-1 or 1. So l can range from 0=s, to 1=p. The ml values represent the orbitals (yes?) so there are 4 orbitals total: for s, there is the ml=0 orbital. for p there is the -1, 0, 1 orbitals.

phew. Is that correct?

THANK YOU again...I really appreciate you taking the time to explain it all for me: test is on thursday and im doing last minute reviewing. My zumdahl text has a million errors.

 

[Rabolisk]

Correct. Finally, the last quantum number, ms, refers to the spin of the electron(s) within the orbital. Do a quick review of Hund's Rule, Pauli Exclusion Principle, Aufbau Principle, etc. if you need to. Remember that half-filled subshells are unusually stable and thus favored.