: 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
It comes from all around us. Any source of electromagnetic energy in the right wavelength can cause an electron to jump up an energy level. If it’s not stable in that orbital it will fall back down and release an equal amount of energy.
Energy is only meaningful relative to something else. You can think of the energy of the electron as how much effort it takes to bring the electron and nucleus together. Since the electron and nucleus are attracted to each other, rhe energy is negative because it takes effort to pull them apart. As you pull them apart, the energy goes up bc you’re preventing them from being together.
Once you’ve pulled them away from each other, it’s easier to pull them further apart. This is why the energy differences are smaller. If you have two magnets you can feel this effect yourself.
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.
Thanks to everyone who has answered, and everyone who’s going to answer
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