Meet the (Most Important) Functional Groups

by James

in Functional Groups, General Chemistry, Organic Chemistry 1, Where Electrons Are

Functional groups are specific groups of atoms within molecules that have very characteristic properties regardless of the other atoms present in a molecule. You’re probably familiar with several of them by now – alcohols, amines, carboxylic acids, ketones, and ethers are all common examples.

How many functional groups are there? Depending on how fine you slice your definitions, dozens and dozens. Wikipedia lists 197 pages for them. Yikes.

Thankfully, the 80/20 rule applies. In a typical sophomore organic chemistry course, there’s about 14 functional groups that are key, with another group of 8 that make appearances from time to time. [You'll meet others, too - this is just a selection of the most common]

Below you’ll find a presentation of the most common functional groups.

Things to think about as you look at the list:

1) in each, what are the most and least electronegative atoms present?

2) which of the atoms will be delta positive and which delta negative?

3) Which functional groups will be capable of hydrogen bonding?

4) Which functional groups will be capable of dipole-dipole interactions?

The more polar the molecule, the stronger the intermolecular interactions and the higher the boiling point.  Which of these functional groups will tend to lead to the greatest increase in boiling points?

The more polar the molecule, the higher the water solubility. Which of these groups will tend to increase water solubility? Decrease water solubility?

Then there’s a group of about 8 functional groups that you’ll see a little but less often but they still have their place:

If you find that you’re having a hard time recalling the structures of the functional groups, I put together aquiz [flashcards on memorize.com] that might be useful.

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{ 6 comments… read them below or add one }

reza October 8, 2010 at 6:47 am

thanks for posting this

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abd April 8, 2012 at 1:52 pm

good, not bad.

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sur April 19, 2013 at 8:40 am

sir the article was really nice and informative but I did not get what I wanted…
my ques is
I hve a substituted benzene with OCH3, NO2 and Br attached at 1, 3, 5 position
so how will I name it?
will it be bromobenzene or nitrobenzene…
and in what order will I number the carbons acc to IUPAC?
PLEASE PLEASE REPLY ASAP..
I will be highly grateful.

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Emily April 20, 2013 at 9:32 pm

This entire website is an amazing resource for MCAT studying. I’m surprised you don’t have a book deal yet. thank you thank you thank you!

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Sara Cameron July 8, 2013 at 4:29 pm

Hello,

I would like to use the diagram from the following page in a coursepack for a course to be held at Fleming College in Ontario, Canada this fall:

http://www.masterorganicchemistry.com/2010/10/06/functional-groups-organic-chemistry/

Can you tell me whether I have permission to do this, or how I can obtain permission?

Many thanks,
Sara Cameron
Canadian Scholars’ Press Inc. (CSPI)

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Tanya August 23, 2013 at 11:31 am

Hi, I’m a bit stuck. I need to find out the boiling points of pentanoic acid and 2-hexanone which I’ve already done, and compared both to find that pentanoic acid has the higher boiling point. I then need to give some sort of example and then justify this but i am not sure how to do so, could you please help?
Thankyou :)

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