Energy levels in an atom

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When I was taught energy levels in a hydrogen atom – I was given the formula ;Energy = -13.6/n^2.

(1)What purpose does that minus sign signify?

(2)If energy in the first Bohr orbit is -13.6 and in the second one is -3.4 is:

(a) The energy in the second orbit greater as
-3.4 > -13.6 or
(b) The energy in the first orbit is greater as
|-13. 6| > |-3.4|?
Is there a better way to look at the energy values (as the minus sign is confusing)?

In: 12

4 Answers

Anonymous 0 Comments

So, any time you express the energy of a state, it’s in reference to something else. To some extent, that reference energy is totally arbitrary; what matters is if the energy of something you’re describing is higher or lower than that reference.

In the case of electrons associated with an atom, the most common reference energy is the state where the electron is at rest and infinitely far away from a nucleus. That state is considered 0 eV.

Now, imagine moving the electron towards a positively charged nucleus. Opposite charges attract, and the energy of the electron goes down the closer you get to the nucleus (until you get really, REALLY close, but that’s >ELI5). Started at 0 and decreasing, energy level of an electron becomes more and more negative the closer you get.

The 1s orbital is closer to the nucleus than the 2s one, so the 2s has a higher energy than 1s.

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