For example, think a carbon atom. It has 6 electrons. Let us name them, like electron Jim, electron Jack,..., electrom Nick. By the Pauli's exclusion principle, no more than one electron can occupy one quantum mechanical eigen state. So that, the electron Jim might be occupying the lowest orbital, the electron Jack the next higher orbital, and so on.
The problem is that they are indistinguishable. Accordingly we cannot specify a particular electron configuration of any carbon atom. That is, we do not know which electron is occupying which orbital. Further they might be exchanging their orbital restlessly.
Is this situation peaceful for your understanding about the atomic electronic structure or about the molecular one? I would like to suggest further a possibility that if a perturbation has nudged on one electron Jim in a giant molecule like an enzyme, then the effect could propagate to the final electron Tom in no time no-locally due to the nemeless nature of the electrons. Do you think this possible? If there are misunderstadings in my story, then please feel free to indicate them. I will be gladly hearing you. Thanks.