Concept
Version 9
Created by Boundless
Periods 1 through 3
![A simplified depiction of atomic structure](../../../../../../../../../figures.boundless-cdn.com/9665/raw/bohr-atom-par.jpg)
A simplified depiction of atomic structure
With the nucleus at the center with a positive charge, the electrons are "organized" in energy levels, or shells, at increasing distances from the nucleus. The distance between the n = 2 and n = 3 shells in this illustration is the difference in energy between them.
Source
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