Carbon Chemistry

Carbon is unparalleled in its ability to form the large, complex, and diverse molecules that characterize living matter.

Because of a bonding capacity of four, carbon can engage in many structurally different bonding arrangements, and play a central role in the shape of organic molecules.

Carbon chains are the skeletons of organic molecules.

Why is carbon so important to the chemistry of living things?

  • Basically, the reason for this is the versatility of structures that carbon can form with itself and with other atoms.
  • Carbon can form four covalent bonds and is capable of forming bonds with a variety of geometries
    • single, double and triple bonds
    • tetrahedral, or flat geometries
    • linear or branching structures
    • polar or non-polar bonds
  • These features allow carbon to form a wide variety of molecules with dramatically different chemical characteristics.

Carbon's versatile bonding is the basis for isomers, molecules with the same molecular formula but different structures and thus different properties. The 3 types of isomers are:

  1. structural isomers,
  2. geometric isomers (cis, trans), and
  3. optical (stereo or chiral) isomers or enantiomers (D, L)

Carbon skeletons vary in length and shape and possess bonding sites for atoms of other elements such as oxygen, nitrogen, sulfur, and hydrogen. When carbon combines covalently with these elements various functional groups are formed.

The specific properties of organic molecules are determined by the various functional groups they contain.

Acetic acid, for example, contains two functional groups, a methyl group and the acidic carboxyl group. The molecular formula for acetic acid is CH3COOH, where -CH3 is the methyl group and -COOH represents the carboxyl group.

The frames below give you a three-dimensional view of the structural formula of acetic acid -- aka vinegar.


Ball and Stick


Practice your knowledge of functional groups by answering the questions below:


The functional group on the right is:

A. an aldehyde

B. an hydroxyl

C. a carboxyl

D. a ketone


The functional group on the right is:

A. an amino group

B. an hydroxyl

C. a carboxyl

D. a ketone


Next page Four Macromolecules