What is Functional groups: Definition and 15 Discussions

In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest of the molecule's composition. This enables systematic prediction of chemical reactions and behavior of chemical compounds and the design of chemical synthesis. The reactivity of a functional group can be modified by other functional groups nearby. Functional group interconversion can be used in retrosynthetic analysis to plan organic synthesis.
A functional group is a group of atoms in a molecule with distinctive chemical properties, regardless of the other atoms in the molecule. The atoms in a functional group are linked to each other and to the rest of the molecule by covalent bonds. For repeating units of polymers, functional groups attach to their nonpolar core of carbon atoms and thus add chemical character to carbon chains. Functional groups can also be charged, e.g. in carboxylate salts (–COO−), which turns the molecule into a polyatomic ion or a complex ion. Functional groups binding to a central atom in a coordination complex are called ligands. Complexation and solvation are also caused by specific interactions of functional groups. In the common rule of thumb "like dissolves like", it is the shared or mutually well-interacting functional groups which give rise to solubility. For example, sugar dissolves in water because both share the hydroxyl functional group (–OH) and hydroxyls interact strongly with each other. Plus, when functional groups are more electronegative than atoms they attach to, the functional groups will become polar, and the otherwise nonpolar molecules containing these functional groups become polar and so become soluble in some aqueous environment.
Combining the names of functional groups with the names of the parent alkanes generates what is termed a systematic nomenclature for naming organic compounds. In traditional nomenclature, the first carbon atom after the carbon that attaches to the functional group is called the alpha carbon; the second, beta carbon, the third, gamma carbon, etc. If there is another functional group at a carbon, it may be named with the Greek letter, e.g., the gamma-amine in gamma-aminobutyric acid is on the third carbon of the carbon chain attached to the carboxylic acid group. IUPAC conventions call for numeric labeling of the position, e.g. 4-aminobutanoic acid. In traditional names various qualifiers are used to label isomers, for example, isopropanol (IUPAC name: propan-2-ol) is an isomer of n-propanol (propan-1-ol). The term moiety has some overlap with the term "functional group". However, a moiety is an entire "half" of a molecule, which can be only a single functional group, but also a larger unit consisting of multiple functional groups. For example, an "aryl moiety" may be any group containing an aromatic ring, regardless of how many functional groups the said aryl has.

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  1. MermaidWonders

    MHB Thioester Isomer Count: ${C}_{4}{H}_{8}OS$ - 4 Possibilities

    How many isomers are there with the following description? - Thioesters with the formula ${C}_{4}{H}_{8}OS$? I was able to draw 2 of them, but apparently, the answer key showed and stated that there are 4. I am confused about why the following two are possibliities: I thought that thioesters...
  2. shihab-kol

    Glycolic acid functional group(s)

    Hey guys, should the -OH group in glycolic acid be considered a functional group or a substituent due to the presence of the carboxylic acid group?
  3. T

    Functional groups in this compound

    Homework Statement Homework EquationsThe Attempt at a Solution I counted 4 functional groups. I got: -Carboxylic acid -Ketone -Alcohol -Ether However, this combination is not available. I was wondering if phenol is a functional group as C seems the most likely option. I thought phenyl is a...
  4. RoboNerd

    Chemistry Question about Molecule Polarity

    Homework Statement I have a methyl orange molecule. Then my problem says that "wool is a protein, a naturally occurring polymer made up of amino acids with ionized side chains. cotton is a naturally occurring polymer made up of glucose units with hydrophillic groups surrounding each glucose...
  5. K

    Properties of -COOR functional group?

    By properties I mean the +I or -I effect as compared to other functional groups along with whether it induces a +R or -R effect?
  6. Τ

    Functional Groups in Alantolactone

    Homework Statement Given the structure of Alantolactone, find two functional groups. 2. The attempt at a solution This was a question that was on my exam recently. I answered Ester and Ether, however Ether was marked incorrect. Instead, only the answers Ester and Alkene were accepted. How is...
  7. A

    Functional groups of organic compounds

    Homework Statement find the functional groups in the following compound: Homework Equations C8H16O4The Attempt at a Solution I know there is an ether but there is also something else. What is it? I have tried to find a group that is in the compound, but I have had no luck. It seems to be only...
  8. S

    Removing Functional Groups from a Molecule: Methods and Possibilities

    Is there a way to "remove" functional groups? I see a lot of pages online that show how you can change them, but not how to completely remove one from a molecule. Is it even possible?
  9. S

    How Can the Energy Stored in Functional Groups be Determined?

    How would I find the amount of energy that is stored in a particular functional group? I know things like Azide, Nitro, Alkynyl, Cyanides, etc. would all store a lot of energy.
  10. W

    Organic Chem - Identifying Functional Groups

    Homework Statement Hi all, i have to identify 5 samples (1,2,3 were solids, 4,5 were liquids) by classifying them as 1) Aliphatic or aromatic and 2) Carboxylic acid, amine (primary, secondary, tertiary) or ammonium carboxylate We did a burn test on the solids, tested solubility in water...
  11. D

    Determining Functional groups - carboxylic acid, ester etc

    Homework Statement What functional groups are present based on the compound's names? A. Methyl Hydroxybenzoate B. 2-Hydroxypropanoic acidHomework Equations The Attempt at a Solution We've learned about the basic Hydrocarbon derivatives in class, but only dealing with problems like...
  12. E

    Functional Groups: Examples of Esters & Ethers

    Could someone please give me an example of an ether and an ester. In words, not drawing them. Thank you!
  13. R

    AP Biology: All 6 Functional Groups

    I was studying my brother's old notes to prepare me for my upcoming AP Biology class. I read over six main functional groups (hydroxyl, carbonyl, carboxyl, amino, sulfhydrl, phosphate) and subsequently, there were follow-up questions. One of them asked to draw a molecule with all of the six...
  14. G

    Functional groups present are: C=O and NH2

    This is about amines: The functional groups present are: C=O and NH2 Why does the N get protonated always but not C=O, since the oxygen has more lone pairs and more electronegative than N so shouldn't the oxygen be protonated more easily? I can't think of any good reasons... please help...
  15. N

    A Carbon skeleton with 2 diff functional groups

    Lets say for example a hydrocarbon skeleton has two diff functional groups branched to the skeleton.. Let's say one of the functional groups pH is less than 9 to 10, and the other functional group's pH is greater than 2 to 4 that means that molecule to be electrically charged, the pH of the...