Chapter 12 “Organic Chemistry: Alkanes and Halogenated Hydrocarbons” and Chapter 13 “Unsaturated and Aromatic Hydrocarbons” considered several kinds of hydrocarbons, but many organic compounds contain atoms other than carbon and hydrogen in their functional groups. A functional group is a specific structural arrangement of atoms or bonds that imparts a characteristic chemical reactivity to the molecule.  Understanding the behavior of a particular functional group allows prediction of chemical and physical properties of a variety of molecules, including biomolecules, that contain that particular functional group.  In this chapter and Chapter 15 “Organic Acids and Bases and Some of Their Derivatives”, we make a brief yet systematic study of some of organic compound families. Each family is based on a common, simple functional group that contains an oxygen atom or a nitrogen atom. Some common functional groups are listed in Table 14.1 “Selected Organic Functional Groups”.

Table 14.1 Selected Organic Functional Groups.  Note that R is usually a hydrocarbon chain.  Cases where R can be an H atom are noted.

Name of Family	General Formula	Functional Group	Suffix*
alkane	RH	none	–ane
alkene	R2C=CR2 The R groups can be Hs.		–ene
alkyne	RC≡CR  The R groups can be Hs.	–C≡C–	–yne
alcohol	ROH	–OH	–ol
thiol	RSH	–SH	–thiol
ether	ROR	–O–	ether
aldehyde	The R group can be H.		–al
ketone			–one
carboxylic acid	The R group can be H.		–oic acid
*Ethers do not have a suffix in their common name; all ethers end with the word ether.