: In atoms, there are various energy levels for electrons. Each energy level has a specific energy. When moving away from the nucleus, the energy increases but the difference between the levels decreases. My question is, where did the energy come from and how does it increase or decrease?

Question

: In atoms, there are various energy levels for electrons. Each energy level has a specific energy. When moving away from the nucleus, the energy increases but the difference between the levels decreases. My question is, where did the energy come from and how does it increase or decrease?

In: Chemistry

Answer 1

When talking about energy in this particular case, it’s the potential energy of electromagnetic interaction. The electrons are negatively charged, the protons in the nucleus are positively charged, and so one is attracted to the other and repelled by the same.

Also, the way this potential energy is defined is in relation to a free electron. So it goes from 0 for unbound and goes down in negative values.

That’s because it represents how much energy you need to transfer to an electron to get it from its bound state to free-floating.

And the simplest way electrons increase or decrease their energy (if they can, because they can only move to unoccupied levels) is by absorbing or emitting photons. Simplest, but not only, as there are some more complex ways of transferring energy between electrons, or between electrons and the nucleus.