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A. Title of the lesson:
- Nomenclature of Alkanes/ Naming Alkanes
B. Objectives
- At the end of the lesson, the students should be able to:
1. Identify the organic molecule parts
2. State the names of straight chain alkanes
3. Discuss the proper steps in naming alkanes
4. Participate activity in class discuss
C. Materials
- PowerPoint Presentation and Multimedia materials.
D. Procedure
Introductory Activity:
1. Greetings, prayer, checking of attendance
2. Motivation- Teacher will group the students into two groups with 3 members
then ask the students to arrange the jumbled letters and paste it on the board. The
first group who get the three correct answer will win and that is the title of the
lesson.
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E. Lesson Proper
Naming Alkanes
The name of every organic molecule has 3 parts:
Parent Name: Indicates the number of carbon in the longest continuous chain.
Suffix: Indicates what functional group is present.
Prefix: Tells us the identity, location and number of substituents attached to the
carbon chain
Names of Straight Chain Alkanes
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E. Lesson Proper
Parent Name: Longest straight carbon chain
Suffix – Our first functional group is alkane, so the suffix is “-ane”
Prefix – Our substituents will be branches in the alkane structure.
A branch is another alkane minus one hydrogen – an alkyl group
Example: if 𝐶𝐻3- is 𝐶𝐻4 minus 1 hydrogen
Since it is a side chain it will replace the –ane suffix with –yl
𝐶𝐻3 - is a methyl group
𝐶𝐻2 𝐶𝐻3 - is an ethyl group
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E. Lesson Proper
Rules or Steps in Naming Alkanes:
1. Find the parent carbon chain and add the suffix
2. Number the atoms in the carbon chain to give the first substituent the lowest number.
3. Name and number the substituents.
-Name the substituents as alkyl groups.
-Every carbon belongs to either the longest chain or a substituent, not both.
-Each substituent needs its own number
-If two or more identical substituents are bonded to the longest chain, use prefixes to
indicate how many: di- for two groups, tri- for three groups, tetra- for four groups, and so
forth.
4. Combine substituent names and numbers + parent and suffix.
-Precede the name of the parent by the names of the substituents.
-Alphabetize the names of the substituents, ignoring all prefixes except iso, as in isopropyl
and isobutyl.
-Precede the name of each substituent by the number that indicates its location.
-Separate numbers by commas and separate numbers from letters by hyphens. The
name of an alkane is a single word, with no spaces after hyphens and commas.
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F. Assessment
I. Direction: Name the following alkanes
1.
4.
2.
5.
3.
6
C-C-C-C-C
C
1
C
1
C-C-C-C-C-C-C
C-C-C-C
C-C-C-C-C-C
C-C-C-C-C-C-C
C
1
1
C
1
C
1
C
1
C
C
1
C
1
C
1
1
C
1
C
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The name of every organic
molecule has 3 parts:
Parent Name: Indicates the number
of carbon in the longest continuous
chain.
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Suffix: Indicates what functional
group is present.
Prefix: Tells us the identity, location
and number of substituents attached to
the carbon chain
prefix paren
t
suffix
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Prefix –
Our substituents will be branches in the
alkane structure.
• A branch is another alkane minus one hydrogen – an alkyl
group
Example: if 𝐶𝐻3- is 𝐶𝐻4 minus 1 hydrogen
Since it is a side chain it will replace the –ane suffix with
–yl
𝐶𝐻3 - is a methyl group
𝐶𝐻2 𝐶𝐻3 - is an ethyl group
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Rules or Steps in Naming Alkanes:
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1. Find the parent carbon chain and add the
suffix.
C – C – C – C – C – C – C – C
C𝐻3
1
C𝐻2
1
Correct
C𝐻2
1
1
C
Note: It does not matter if the chain is straight or it bends.
8 atoms in the longest chain
8 C’s octane
C – C – C – C – C – C – C – C
C
1
C
1
C
1
1
C
C – C – C – C – C – C
1
C
1
C
C
1
C- C
1
C -
- C – C – C
C
1
C
1
- C
C-C
1
- C – C - CC
8 C’s in the longest chain of
each representation
H
1
H -
I
H
H
1
H
1
H
1
H
1
H
1
I
H
I
H
I
H
I
H
I
H
I
H
- H
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2. Number the atoms in the carbon chain to give the first
substituent the lowest number.
15
Correct
C – C – C – C – C – C – C – C
C
1
C
1
C𝐻2
1
1
C
1 2 3 4 5 6 7 8
Start numbering
here.
First substituent at C2
Incorrect
C – C – C – C – C – C – C – C
C
1
C
1
1
C
C
1
8 7 6 5 4 3 2 1
First substituent at C3
H
1
H
1
H
1
H
1
H
1
H
1
I
H
I
H
I
H
I
H
I
H
I
H
I
H
H - -H
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If the first substituent is the same distance from both ends,
number the chain to give the second substituent the lower
number.
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Numbering from left to right
C – C – C – C – C – C – C – C
C
1
C
1
1
C
1 2 3 4 5 6 7 8
CH3 groups at C2, C3, and
C7.
The second substituent has a lower
number
Numbering from left to right
Correct
C – C – C – C – C – C – C – C
C
1
1
C
C
1
8 7 6 5 4 3 2 1
CH3 groups at C2, C4, and
C7.
higher
numberIncorrect
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When numbering a carbon chain results in the same numbers
from either end of the chain, assign the lower number
alphabetically to the first substituent
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Numbering from left to right
C – C – C – C – C – C – C – C
C
1
1
C
1
C
1 2 3 4 5 6 7 8
• Ethyl at C3
• Methyl at
C7
Numbering from right to left
Correct
C – C – C – C – C – C – C – C
C
1
8 7 6 5 4 3 2 1
• Methyl at C3
• Ethyl at C7
Incorrect
Ethyl
group
Methyl
group
1
C
1
C
Methyl
group
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3. Name and number the substituents.
-Name the substituents as alkyl groups.
-Every carbon belongs to either the longest chain or a
substituent, not both.
-Each substituent needs its own number
-If two or more identical substituents are bonded to the
longest chain, use prefixes to indicate how many: di- for
two groups, tri- for three groups, tetra- for four groups,
and so forth.
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C – C – C – C – C – C – C – C
C
1
C
1
C
1
1
C
1 2 3 4 5 6 7 8
Methyl at C2
Longest chain
8 C’s octane
Ethyl at C4
Methyl at C6
This molecule has three
substituents bonded to the
longest carbon chain.
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4. Combine substituent names and numbers + parent and
suffix.
-Precede the name of the parent by the names of the substituents.
-Alphabetize the names of the substituents, ignoring all prefixes except
iso, as in isopropyl and isobutyl.
-Precede the name of each substituent by the number that indicates its
location.
-Separate numbers by commas and separate numbers from letters by
hyphens. The name of an alkane is a single word, with no spaces after
hyphens and commas.
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20.
21.
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I. Direction: Name the following alkanes
1.
4.
2.
5.
3.
22
C-C-C-C-C
C
1
C
1
C-C-C-C-C-C-C
C-C-C-C
C-C-C-C-C-C
C-C-C-C-C-C-C
C
1
1
C
1
C
1
C
1
C
C
1
C
1
C
1
1
C
1
C
H
1
H
1
H
1
I
H
I
H
I
H
I
H
I
H
H - - H
