## Energy Levels [ENDORSED]

Vincent Chiang 1L
Posts: 54
Joined: Fri Sep 29, 2017 7:05 am

### Energy Levels

In discussion we discussed energy levels and changes in energy (delta E), absorption, and emission. We were told that E (photon) = delta E. I understand that absorption of photons results in increased energy levels (n), with delta E being positive. I was curious, in emission, since photons are ejected and thus energy is lost, shouldn't delta E be negative? We were talking about this in discussion and my TA said the energy of the photon should never be negative. Thanks in advance.

Kyle Reidy 3H
Posts: 19
Joined: Fri Sep 29, 2017 7:06 am

### Re: Energy Levels  [ENDORSED]

A photon has a discrete amount of energy, E = hv. This number is always positive, since the photon cannot have "negative" energy. When an atom emits a photon, it loses an amount of energy, so yes, ΔE for the atom would be negative. We describe this loss of energy as the emission of a positive amount of energy.

Tasnia Haider 1E
Posts: 55
Joined: Sat Jul 22, 2017 3:01 am

### Re: Energy Levels

Since the electron is returning to the ground state, it is emitting energy, which would be a negative number. However, this number is used to find wavelengths, and the calculation can't have a negative energy because then it would result in a negative wavelength, which isn't possible. The energy is also a change of energy which should be an absolute value, which is positive.