### "Discrete" units

Posted:

**Sun Apr 15, 2018 11:52 pm**In lecture, Professor talked about how light is absorbed/emitted in discrete units. What does "discrete" mean? Sorry, this might seem like a dumb question, but I am confused.

Created by Dr. Laurence Lavelle

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https://lavelle.chem.ucla.edu/forum/viewtopic.php?f=16&t=30831

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Posted: **Sun Apr 15, 2018 11:52 pm**

In lecture, Professor talked about how light is absorbed/emitted in discrete units. What does "discrete" mean? Sorry, this might seem like a dumb question, but I am confused.

Posted: **Mon Apr 16, 2018 12:51 am**

Discrete just means that there is a finite number as opposed to a continuous amount. In regards to chemistry, we describe energy as being transferred in discrete units or packets.

Posted: **Mon Apr 16, 2018 3:49 pm**

For example, electrons can only exist at certain energy levels. So electrons jump up from n=1 to n=2, or down from n=4 to n=3, absorbing or releasing photons (energy packets) with discrete energy values. They could never exist between energy levels (i.e. at n=1.34) and therefore there are only certain energy values that they can release and absorb.