- Carbon has a valence of 4 which makes
it capable of entering into 4 covalent bonds.
- This situation allows carbon to form many
different chemical compounds. The following are variations in
which carbon may form different chemical compounds:
- 1). Length of the carbon skeleton may differ (
C-C, C-C-C, C-C-C-C-C,
- 2). Branching of the carbon skeleton
- 3). The number of double bonds may differ (
C=C-C-C, C=C=C-C ).
- 4). The molecular structure may be in a ring
- Chemical compounds with the same molecular
formula but different structural formulas is called an
- There are 3 types of
- a). Structural:
These isomers differ from others due to the differing covalent
arrangements of the atoms.
- b). Geometric:
These isomers contain the same covalent arrangement but different
spatial arrangements. The double bonds make the molecule rigid
which prevents atomic rotation.
- c). Optical:
These isomers are mirror images of one another. There are right
and left handed versions of these compounds. The asymmetrical
carbon, this is the carbon that is attached to 4 different groups,
revolves causing the isomer to occur. The left handed isomer
usually functions in nature, while the right has no use or can
cause problems in the organism using it.
- Functional Groups: These are
certain groups of atoms attached to the carbon skeleton. This area
is usually on the end of the molecule. This region is the focus of
most chemical reactions. These groups change the activity and
function of the molecule they are added to.
- 1. Hydroxyl R- OH makes molecule polar
and produces an alcohol.
- 2. Carbonyl R=O produces compounds
known as ketones and aldehydes
- 3. Carboxyl R=O and OH forms organic
acids (carboxylic acids: formic, acetic, etc.).
- 4. Amino R- N + 1 charge, usually
basic, acts as a good buffer.
- 5. Sulfhydral R- S-H thiols, stabilizes
protein molecular structures.
- 6. Phosphate R- O- P- O plus 2 more Oxygens
attached to the P. energy storage that can be passed on from
one molecule to another by the transfer of the group.
Alkanes: Hydrocarbons containing 1 single
covalent bond. Examples: Methane (CH4), ethane
(C2H6), propane, butane, pentane, hexane, and
heptane. Their boiling point increases as the molecules get
Alkenes: Carbons are connected with double
bonds. Example ethylene (C2H4), propene
(C3H6). Rotation does not occur around the
Alkynes: Triple bonds connecting the
carbons. Acetylene (C2H2).