This chapter begins with the study of the simplest organic molecules:
hydrocarbons.
Of the hydrocarbons, the most basic molecules are alkanes, which consist of only
single bonds. Alkanes may be unbranched, branched, or cyclic. In addition to
our examination of Alkanes, we will also take a brief look at alkenes and
alkynes, which contain double and triple bonds. These molecules can be named
using the
IUPAC nomenclature system, which systematically and unambiguously identifies any
molecule. Because organic chemists tend to draw lots of large molecular
structures,
several shorthand notations are frequently used, including condensed structures,
line-angle drawings and abbreviations for constituent groups.
We also introduce the extremely prevalent concept of isomerism: different
molecules with the same molecular formula. There are two types of isomers.
Constitutional isomers differ in the connectivity of bonds, whereas
stereoisomers have the same bond connectivities
but have bonds oriented differently. Stereoisomerism is exhibited by alkenes
due to the rigidity of pi-bonds, but we'll see in the next chapter that stereoisomerism
is a much more general phenomenon that occurs in a wide variety of compounds.
