Organic Molecules Chapter 20

Organic Chemistry Two essential elements are located in column 14 of the periodic table: Carbon Silicon Silicon bonds with four single bonds or less multiple bonds to form the fundamental compounds in the earth. Carbon similarly bonds in long chains making up essential organic molecules of life.

Carbon Bonding Carbon forms four bonds with itself or other atoms. More than any other element carbon has the ability to form long chains. Carbon forms compounds with either single (CH4 Methane), double (C2H4 Ethylene) or triple bonds (C2H2 Acetylene).

Shapes of Molecules Organic molecules follow the rules of VSEPR Valence Shell Electron Pair Repulsion

Alkanes Hydrocarbons are compounds made up of carbon and hydrogen Saturated hydrocarbons have all single bonds on the carbons Unsaturated hydrocarbons have at least one carbon with a multiple bond (Alkynes and Alkenes) Hydrocarbons use a simple naming scheme assigned by the number of carbons

Isomers Structural Isomerism occurs when two molecules have the same number of atoms but different bonds. Butane (C4H10) and all larger Alkanes exhibit structural isomerism.

Isomers of Pentane

Naming Alkanes

Naming Alkanes Non branched Alkanes are named as in Table 20.1 Branched hydrocarbons are named by the carbon length of the longest chain. When an alkyl is substituted for a hydrogen bonded to the carbon; the location, name of substituent, and Alkane are given in the name.

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