Aromaticity

(Speaking to my 15 year old brother)

Benzene is the easiest compound to use when trying to explain aromaticity. Benzene is a six carbon ring with alternating double bonds (3 π bonds).

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 This is a picture of Benzene. Each point of the ring represents a carbon atom. The three extra lines you see represent double bonds, also called π bonds. A chemical bond is simply and attraction between two atoms. A double bond simply means there are two bonds between the atoms and the electrons are shared.

Aromaticity describes the special stability that Benzene has because of the structure. Since Benzene is considered Aromatic is follows Huckel’s rule. This criteria is as follows:

The molecule must cyclic which means there is a ring of atoms. It is easy to tell that the atoms are placed in a ring by drawing a circle around the molecule.

The molecule must be planar which means that all atoms in the molecule must lie in the same plane.

3.      The molecule has to be completely conjugated which means there has to a p orbital on very atom. A p orbital explains the wave-like behavior of the electrons. Below is a picture of the Benzene molecule drawn with a p orbital on each atom.

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 And finally, the molecule must contain 4n+2 π electrons. This confirms that the molecule is stable because all the bonding orbitals are filled with paired electrons. You can count the number of π electrons a molecule has and set this equation equal to that number. If n is equal to 0 or any other positive number the rule has been met.  A π electron resides in a π bond. 3 π bonds = 6 π electrons because there are 2 π electrons in each double bond. Here is an example of how to confirm this rule applies using Benzene.

4n + 2 = 6

4n = 4

n = 1

Since n is a positive integer, the rule is confirmed.