The word "energy" used in different scenarios

[JTieu_1L]

When the book refers to higher energy or lower energy, does it mean the energy of the electron or the energy of the atom? Or does it refer to energy level? For example, the book mentions energies in orbitals are degenerate in H-atoms, what does the word "energy" mean in this context? Another example, "an s-electron is bound more tightly than a p-electron and has a slightly lower (more negative) energy". What does energy mean here? Does it mean the same? Another example "At first sight, it might seem that an atom should have its lowest energy when all its electrons are in the lowest energy orbital (the 1s-orbital)".

Overall question: What does the word "energy" really mean or is referring to?

[Lindsey_Su_3A]

I believe it is referring to the energy of the electron. When the electrons are farther from the nucleus (higher energy level), they have a higher energy.

[Melody Wu 2L]

Right now this unit is more focused on the positions and transitions of electrons within the atom, so "energy" should be related to the electron since it's the one that is typically changing.

[Nan_Guan_1L]

yeah I agree that it should be referring to electrons, especially in this scenario you are describing. And from what we've learned in class, I think most of the times when we say "energy" we would be referring to electrons, since they are the ones moving around and generally exhibiting energy.