Carbon is a fascinating element that is capable of forming four covalent bonds.

Carbon is a fascinating element that is capable of forming four covalent bonds.

Remembering molecular geometry, an element bonded to four separate atoms forms a symmetrical tetrahedron. When the elements are either carbon or hydrogen the molecule is nonpolar. Nonpolar compounds are insoluble in water. Examples of this include oils, paraffins, and gasoline.

Table 10.2 p. 278 of your text introduces functional groups. Functional groups are regions on a molecule that give the molecule a certain reactivity. They arise when the normal symmetry of the hydrocarbon is changed. For instance, when a double or triple bond forms the molecule is altered at that region to a planar or linear arrangement. When oxygen, nitrogen, or other atoms are added the molecule it may become polar.
Certainly, the reactivity of the molecule is changed.

Think of your body as a large molecule. Your hands, feet, eyes, ears, nose, mouth, etc, are all functional groups. Discuss how a utensil such as a fork is designed to work with one or two 'functional' groups. Relate this to one of the reactions you see represented in chapter 11 or 12.