Factors Affecting Electron Energy in Multi-Electron Atom

[David Chibukhchian 2G]

Hey guys, I was going over the quantum section to review for this week's midterm and I realized I was a bit confused about one of the topics. Specifically, it's the bullet point on outline 2 that says "Describe the factors affecting the energy of an electron in a multi-electron atom." Does this basically refer to the fact that shielding and the structure of the subshells is the reason that multi-electron atoms aren't degenerate like hydrogen is? I'm a bit unsure in general about this. If anyone could explain it a bit that would be really helpful!

[EnricoArambulo3H]

Yes, shielding would be one of the factors that affect electron energy in a multi-electron system, since the interactions between electrons can influence its potential energy. I think an effective nuclear charge and the type of orbital state the electron is in can also influence its energy since the protons can also exhibit an electrostatic attraction with the electrons, but that is also dependent on shielding. I hope this helped!

[Samantha Pedersen 2K]

I think some other factors that affect the energy of an electron in a multi-electron atom are its principal quantum number (n) and its angular momentum quantum number (l). This is because electrons with a higher value of n are farther away from the nucleus and therefore have higher energies. The value of l also plays a role because P subshells are higher in energy than S subshells, and D subshells are higher in energy than P subshells.

I also found this old Chemistry Community post with more discussion of this topic: viewtopic.php?t=22835#:~:text=A%20factor%20that%20affects%20electron,nucleus%20and%20the%20outer%20electron.

I hope this helps!

[Kareena Patel 1G]

Yes, it involves shielding and the effective nuclear charge. I think it may also refer to ionization energy and electronegativity as well.

[Samiha Molla 3G]

I had the same question about this objective, and I think the others are right that it's mainly referring to shielding!

[David Chibukhchian 2G]

Yeah, the fact that shielding is going to affect the energy of the electrons in multi-electron atoms seems to be important, and it definitely makes sense. I also found that older post to be helpful, as it explained how both shielding and the presence of nodes are going to be the reason why we don't see degenerate subshells in elements that aren't hydrogen. That really helps, thank you all!