The Beechmont Crest Online Guide to Organic Chemistry
ELECTRON SHELLS AND SUBSHELLS
Electrons spin around the nucleus of an atom in concentric shells and subshells. Electron shells have principle quantum numbers (1,2,3, etc.). These numbers are used to identify the level of the shell.
As the quantum number of a shell increases, the energy of the shell increases. There is also a greater distance between the electrons in shells with higher principle quantum numbers. Moreover, the higher the principle quantum number, the greater the distance from the nucleus.
Level 1 therefore represents the lowest energy level, and the electrons in this level are the closest to the nucleus. The distance from the nucleus (and the energy level) increases with Level 2, and so on.
