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.
Homework
• Page 744
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