aromatic...or..not..

[cocokeala]

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hello sorry i really thought i understood aromaticity from my kaplan class but i dont get this topscore question. ochem test1 #98 hehe can someone explain that to me because most of them look nonaromatic to me 😕 thanks!

 

[vha7777]

The way I went about answering the question is to pick the molecule that was least stable and most likely to react. Aromaticity is supposed to be related to the most stable config. so I just thought that if something is anti-aromatic then they should be least stable. All of the choices are non aromatic but the answer has the two *free electrons" so they will be more reactive then the other choices. Not sure if this is the right reasoning but that's how i got the answer.

 

[714guy]

hello sorry i really thought i understood aromaticity from my kaplan class but i dont get this topscore question. ochem test1 #98 hehe can someone explain that to me because most of them look nonaromatic to me 😕 thanks!

use the 4n+2 rule, n being any number 0,1,2,3,. . . Count the # of pi bonds and then the lones pairs and multiply by two and if that equals the 4n+2 for any n its aromatic.

i.e. A benzene ring has 3 pi bonds X 2 (electrons per bond) + 0 Lones pairs X 2 electrons = 6 which is equal to 4(1) + 2 = 6 so its aromatic.

Now look at Cyclobutadiene, it has 2 pi bonds X 2 = 4 that doesn't equal and N in the 4n+2. therefore its not aromatic

 

[cocokeala]

OOO thanks they are asking for the least stable since they are all nonaromatic?