Organic
Nomenclature
Alkanes
SWBAT: Name alkanes with
alkyl groups
Organic Chemistry
 The
study of the structure, properties,
composition, reactions, and preparation
(synthesis) of carbon-based compounds,
hydrocarbons and their derivatives
Organic Molecules



Organic molecules are compounds consisting
of nonmetals (hydrogen, nitrogen, oxygen,
the halogens, phosphorus, silicon and sulfur)
with carbon
Due to carbon’s hybrid bonding orbitals,
organic molecules have a variety of
configurations
The types of atoms bonded to the carbon
atoms will ultimately determine function and
properties of the compound
Organic vs. Inorganic
General Comparison
Organic Compounds
 Mostly
covalent
bonding
 Low boiling pt
 Low melting pt
 High flammability
 Most are nonpolar
 Not soluble in water
unless a polar group is
present
 Do not conduct
electricity
Inorganic Compounds
 Many
ionic, some
covalent
 High boiling pt
 High melting pt
 Low flammability
 Most are ionic or polar
covalent
 Most are soluble in
water unless nonpolar
 Conduct electricity
Hydrocarbons
A
hydrocarbon chain is a series of
carbons bonded together with numerous
hydrogen's attached
 Includes Alkanes, Alkenes, Alkynes and
Cyclical HC
 Use certain prefixes for naming to indicate
chain length
Alkane Formulas and Names
 Strings,
branches of carbons with single
bonds between C
 Essentially many CH4 reacted together
 Formula rules: CnHn+2
 CH2 – methylene unit
 Names: Prefixes indicate # of C followed
by -ane
Homologous series of the first
12 linear alkanes
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Methane
Ethane
Propane
Butane
Pentane
Hexane
Heptane
Octane
Nonane
Decane
Undecane
Dodecane
(meth=1)
(eth =2)
(prop=3)
(but=4)
(pent=5)
(hex=6)
(hept=7)
(oct=8)
(non=9)
(dec=10)
(undec = 11)
(dodec= 12)
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
C7H16
C8H18
C9H20
C10H22
C11H24
C12H26
1-10 Alkane Prefix Quiz
Just the prefix…not the -ane
1. CH4
6. C6H14
3. C3H8
8. C8H18
2. C2H6
4. C4H10
5. C5H12
7. C7H16
9. C9H20
10.C10H22
Mnemonic for First 8 Prefixes
 Mrs.
Edwards Plays Basketball,
Please Hold Her Overcoat
 Methane
 Ethane
 Propane
 Butane
 Pentane
 Hexane
 Heptane
 Octane
CH4
C2H6
C3H8
C4H10
C5H12
C6H14
C7H16
C8H18
Alkane Naming and Drawing
1.
Expanded structure
1. Make string of carbons (prefix= # of C)
Ex: Butane (but=4)
Butane
2. Condensed structure A
CH3-CH2-CH2-CH3
3. Condensed structure B
CH3CH2CH2CH3
4. Condensed structure C
CH3(CH2)2CH3
Butane
5. Carbon skeleton: C-C-C-C
*all H are understood
6. Kekulé or Line-angle formula
(most reduced form)
• Each endpoint, every corner symbolizes a C
• H are understood
Alkanes
methane
hexane
CH4
C6H14
ethane
heptane
C2H6
C7H16
propane
octane
C3H8
C8H18
butane
nonane
C4H10
C9H20
pentane
decane
C5H12
C10H22
Alkyl Groups
 Substituent
– element or group of elements
that branch off parent chain (replace a H)
 methyl
 ethyl
group
group
 propyl
group
Alkyl Groups
 isopropyl
 butyl




groups
butyl
secbutyl
tertbutyl
isobutyl
Only iso- is alphabetized,
tert, sec are not.
Haloalkanes
 Haloalkanes
have a halogen that has
replaced a hydrogen
 The halogens are substituent groups
treated the same as the alkyl groups.
Alpha without prefixes
F = fluoro
Cl = chloro
Br = bromo
I = iodo
Rules to Naming Hydrocarbon
Chains
1.
Number the longest continuous chain of carbons
1.
2.
2.
Carbons attached to double/triple bonds receive the
smallest number possible
If no double/triple bonds are present, carbons with
groups attached, receive the smallest number possible
Use prefixes for repeating groups
di, tri, tetra, penta, hexa, ….
3.
4.
5.
Alphabetize groups without prefixes
All lowercase, commas between numbers, dashes
between numbers and words
Use appropriate ending

ane, ene, yne or functional group ending
Find The Longest Continuous
Chain of Carbons
Number the Carbons so that
the groups receive the
smallest number possible
Use prefixes with same multiple
substituent groups
7 – ethyl – 3,5 - dimethyl – 6 - tertbutylundecane
Naming Hydrocarbon Chains
Naming Hydrocarbon Chains
Naming Hydrocarbon Chains
If more than one type of
substituent group, alpha. the
groups without prefixes
5 – secbutyl - 3,6 – dimethylnonane
4 – tertbutyl - 5 - ethylnonane
Cycloalkanes
1. Start at noon and go clockwise until you
get to first carbon with a substituent group
this is # 1
2. Go clockwise or counterclockwise so
substituent groups receive the smallest
number possible
Cyclical Alkanes
have 2 H less from ring closure
cyclopropane
C3H6
cyclooctane
C8H16
cyclobutane
cyclononane
C4H8
C9H18
Alkanes
 cyclodecane
C10H20
 cycloundecane
C11H22
 cyclododecane
C12H24
Practice
methylcyclopentane
1,1-dimethylcyclopentane
Practice
1,2-dimethylcyclopentane
1,3-dimethylcyclopentane
Practice
2-ethyl,1-methylcyclohexane
Practice
2-cyclopropyl-4-ethyl-1-methylcyclohexane