Organic Chemistry
Nomenclature:
Alkanes
Alkenes
Alkynes
Alkanes – Page 7

Hydrocarbons – made of carbon and
hydrogen
◦ Saturated – all single bonds

Formula = CnH2n+2
Prefixes for # of Carbons – Page 5
1
Meth
6
Hex
2
Eth
7
Hept
3
Prop
8
Oct
4
But
9
Non
5
Pent
10
Dec
Name
Methane
Ethane
Propane
Butane
2-Methylpropane
Molecular
Formula
CnH2n+2
Structural Formula
Model
Summary: IUPAC Rules for Alkane
Nomenclature
1. Find and name the longest continuous carbon chain. This is
called the parent chain. (Examples: methane, propane, etc.)
2. Number the chain consecutively, starting at the end nearest
an attached group (substituent).
3. Identify and name groups attached to this chain. (Examples:
methyl-, bromo-, etc.)
4. Designate the location of each substituent group with the
number of the carbon parent chain on which the group is
attached. Place a dash between numbers and letters.
(Example: 3-chloropentane)
5. Assemble the name, listing groups in alphabetical order.
The prefixes di, tri, tetra etc., used to designate several
groups of the same kind, are not considered when
alphabetizing. Place a comma between multiple numbers.
(Example: 2,3-dichloropropane)
Step 1. Find the parent chain.

Where is the longest continuous chain of
carbons?
Step 2. Number the parent chain.

Number the parent chain so that the attached
groups are on the lowest numbers
Methyl is on carbon #2 of the parent chain
Methyl is on carbon #4 of the parent chain
1
5
1 8
2
4
3
3
4
2
3 6
7 2
8 1
4 5 5 4
6 3
5
1
GREEN is the right way
for this one!
27
1
7
2
6
3
5
Groups on 2 and 5
Groups on 4, 6, and 7
Groups on 2, 3, and 5
4
4
5
3
6
72
1
Groups on 3 and 6
Step 3. Name the attached groups.

Carbon (alkyl) groups
◦ Methyl CH3 ◦ Ethyl CH3CH2◦ Propyl CH3CH2CH2 –
Step 4. Designate where the group is
attached to the parent chain.

Use the numbers of the parent chain from
step 2 to designate the location of the
attached groups to the parent chain.
Step 5. Alphabetize the groups, combine like
groups, and assemble.
The prefixes di, tri, tetra
etc., used to designate
several groups of the same
kind
 Prefixes are not considered
when alphabetizing
(Example: dimethyl = m for
alphabetizing)
 Parent chain goes LAST

1,1,1-trichloro-1fluoromethane
1,1-dichloro-1,1difluoromethane
Final Names
Review Notes – Page 6 (Blank)

1. Name the Parent Chain
◦ With –ane ending

2. Name the Side Chains
◦ With –yl ending

3. Number the Parent Chain
◦ Groups have lowest numbers possible

4. Put It All Together
Example 1: 3-ethylheptane
Example 2: 2,7-dimethylnonane
Example 3: 4-ethyl-2,4,5-trimethyloctane
Example 4:
3,3,4,4-tetraethyl-2,2,5,5-tetramethylhexane
Name Alkanes – Page 9
Draw Some Simple Alkanes – Page 9

2-methylpentane

2,3-dimethylbutane
Homework Review – Pages 17&18
Name
1.
dodecane
2.
2-methylheptane
3.
2,3,4-trimethylhexane
Structural Formula
Cycloalkanes
Are ring structures
 Formula = CnH2n

Isomers – Page 19

Draw butane and 2-methylpropane.
Isomers – Page 19

Draw pentane, 2-methylbutane, and 2,2dimethylpropane.
Alkenes – Page 10
Naming Alkenes – Page 10
Drawing Alkenes – Page 11
1-hexene
2-methyl-4-ethyl-1-nonene
Alkynes – Page 12
Naming Alkynes – Page 12
Drawing Alkenes – Page 12
2-hexyne
4-ethyl-1-nonyne
Naming Alkenes and Alkynes
IUPAC nomenclature rules for alkenes
and alkynes are similar to alkanes.
 Step 1. Name the parent compound.
Find the longest chain containing the
double or triple bond, and name the
parent compound by adding the suffix –
ene or –yne to the name of the main
chain.

Step 2: Number the carbon atoms in the parent
chain, beginning at the end nearest to the double or
triple bond. If the multiple bond is an equal distance
from both ends, begin numbering at the end nearer
the first branch point. The number indicates which
carbon the multiple bond is AFTER. (i.e. between 2
and 3 is 2-)
 Step 3: Assign numbers and names to the
branching substituents, and list the substituents
alphabetically. Use commas to separate numbers, and
hyphens to separate words from numbers.

Step 4. Indicate the position of the
multiple-bond carbon. If more than one
multiple bond is present, identify the position
of each multiple bond and use the
appropriate ending diene, triene, tetraene,
and so forth.
 Step 5. Put it all together.

Naming Alkenes and Alkynes
When the carbon chain has 4 or more C atoms,
number the chain to give the lowest number to the
double or triple bond.
CH2=CHCH2CH3
CH3CH=CHCH3

CH3C CCH3
Aromatic Compounds – Page 13



In the early days the word aromatics was
used to described many fragrant
molecules isolated from natural sources.
Today the term aromatic is used to
describe benzene-like molecules.
Benzene is a flat, symmetrical molecule
with the molecular formula C6H6.
It has alternating three carbon-carbon
double and three single bonds.
Simple aromatic compounds like benzene are
non-polar, insoluble in water, volatile, and
flammable.
 Unlike alkenes, several aromatic hydrocarbons
are toxic. Benzene itself is implicated as a
cancer causing chemical.

Aromatics – Page 13


Benzene’s is C6H6.
There are two possible structures with
alternating double and single bonds.
Naming Aromatics
Benzene = Parent Chain
 Number branches

Alkyl Halides – Page 27
 Halocarbons - class of organic
compounds containing covalently
bonded fluorine, chlorine, bromine,
or iodine
◦ General formula: R-X (X = halogen)
 Fluorine
 Chlorine
 Iodine
 Bromine
Naming Alkyl Halides