1. One of carbon's interesting properties is its ability to form a wide variety of molecules, especially ones containing bonds linking multiple carbon atoms.

2. This element is so widely distributed throughout nature that the largest subdiscipline of chemistry, organic chemistry, is devoted to the study of carbon compounds.

3. The name organic is historical and suggests a biological origin for the substances under investigation, but this is not necessarily true.

4. In practice, most organic chemists confine themselves to compounds in which carbon is combined with a relatively small number of other elements: hydrogen, oxygen, nitrogen, sulfur, chlorine, phosphorus, and bromine.

5. Even with this restriction, over 12 million of the 23 million total known compounds are considered organic.

6. The chemical behavior (i.e., properties and reactivity) of organic compounds enables us to organize them into a relatively small number of categories.

7. As a result, in this chapter we concentrate on only a few and stress their important roles within the functions of living things.

8. To identify a specific organic compound from among the myriad of possibilities, the compound must be named.

9. Chemists use a formal set of nomenclature rules established by an international committee so each of the 12 million compounds can be uniquely named.

10. However, many of these compounds have been known for a long time by common names such as alcohol, sugar, and morphine.

11. When a headache strikes, even chemists do not call out for 2-(acetyloxy)-benzoic acid; they simply say "Give me some aspirin!"

12. Likewise, prescriptions specify penicillin-N rather than 6[(5-amino-5-carboxy-l-oxopentyl)amino]-3,3-dimethyl-7-oxopentyl-4-thia-l-azabicyclo[3.2.0]hepta-ne-2-carboxylic acid.

13. Mouthfuls like this are the cause of great merriment to those who like to satirize chemists. Nonetheless, chemical names are important and unambiguous to those who know the system.

14. You can rest easy because in this chapter, we will use common names in almost all cases.

15. An incredible variety of organic compounds exists because of the remarkable ability of carbon atoms to bond in multiple ways both to other carbon atoms and to atoms of other elements.

16. To better understand such possibilities, we need a few basic rules for bonding in organic molecules.

17. You used one of these in Chapter 2, the octet rule.

18. When bonded, each carbon atom has a share in eight electrons, an octet.