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2. ORGANIC COMPOUNDS
FAMILIES OF CARBON COMPOUNDS: FUNCTIONAL
GROUPS
General Chemistry 1
ROMINA D. MEDIANA

3. Learning Competency:
Describe the different functional
groups (STEM_GC11OCIIg-j-87)
Specific Objectives:
1. Describe the major functional groups in organic chemistry and
name organic compounds;
2. Recognize from the structural formula which class of organic
compounds a certain molecule belongs; and
3. Identify all the functional groups present in a molecule given its
structural formula.

4. Organic Chemistry
o are compounds containing one or more
atoms of carbon EXCEPT oxides of carbon
(e.g., CO and CO2); carbides (e.g., CaC2,
commonly known as “kalburo”); cyanides
(e.g., NaCN); carbonates (e.g., CaCO3);
hydrogen carbonates or bicarbonates
(e.g., NaHCO3); and allotropes of carbon
(e.g., diamond, graphite, graphene, and
fullerenes such as buckminsterfullerene, or
C60).
o is the study of the chemistry of carbon-
containing compounds.

5. SAMPLES OF
ALLOTROPES OF
CARBON

6. THE
UNIQUENESS
OF
◦ Carbon can form four covalent bonds.
◦ It forms strong bonds with a variety of elements,
especially H, O, N, and the halogens.
◦ Carbon also has an exceptional ability to bond to
another carbon atom/s forming a variety of
molecules made up of chains
(straight/unbranched, branched, or cyclic) of
carbon atoms in endless arrays.
CARBON
ATOM
Electron
configuration:
1s2 2s2 2p2

7. Molecular formula
◦is a chemical formula that indicates the
actual numbers of atoms present in a
molecule.
For example,
the molecular formula CH4 tells us that methane has one
carbon atom and four hydrogen atoms.

8. Structural formula
◦ displays the atoms of the molecule in the order they are bonded. It
also depicts how the atoms are bonded to one another. There are
four types of structural formulas: electron-dot formula, dash formula,
condensed formula, and bond-line formula or skeletal formula.
Examples of these four types are shown below using 1-propanol as
an example.
FIGURE 1: Ball-and-stick model and structural formulas for 1-propanol

9. ◦ Bond-line formulas are easy to draw for molecules with multiple bonds and for cyclic molecules,
as well. The following are some examples.

10. Hydro
carbons
- are compounds that
contain only carbon and
hydrogen atoms.
- are further classified into
aliphatic hydrocarbons
(those that do not
contain benzene ring)
and aromatic
hydrocarbons (those that
contain benzene ring).
- Names of hydrocarbons
end in -ane, -ene, or -yne
which then tell us what
kinds of carbon–carbon
bonds are present.
- The name of the parent
compound is determined
by the number of carbon
atoms in the longest
chain.

11. The Four
Hydrocarbon
Types

12. ALKANE
- contain only carbon-
carbon single bond
(C―C), and this is
indicated in the family
name and in names for
specific compounds by
an -ane ending.
- Alkanes, except
cycloalkanes, have the
general formula CnH2n+2
where n=1, 2, 3, ….
- also known as
saturated hydrocarbons
because these
compounds contain the
maximum number of
hydrogen atoms that
can bond to carbon
atoms present

13. Structural
Isomers
 are different
compounds that have
the same chemical
formula.
 Compounds that
have the same
molecular formula but
different bonding
arrangements (and
hence different
structures)
There are two ways of
writing the structure of
butane:
1. n-butane (where n
stands for normal,
straight)
2. Isobutane (branched
chains)
n-butane
straight chain
Boiling Point = -42.1oC
isobutane
branched chain
Boiling Point = -11.7oC
 For alkanes, the number of isomers increases as the number of carbon atoms
increases. While butane has only 2 isomers, decane has 75 isomers and the alkane
C30H62 has over 400 million possible isomers.
 While many of these do not exist in nature, this illustrates how carbon forms more
compounds than any other element.
 The structural isomers of a given alkane differ slightly from one another in physical
properties, as the melting and boiling points

14. Structural
Isomers

15. EXAMPLE
OF
ISOMER
How many structural isomers can be identified for pentane, C5H12?
◦ Solution The first step is to write the straight-chain structure:

16. Alkyl Groups
and the
Symbol R
Alkyl groups are the
groups that would be
obtained by removing a
hydrogen atom from an
alkane. These alkyl groups
have names that end in
-yl.
When the alkane is
unbranched, and the
hydrogen atom that is
removed is a terminal
hydrogen atom, the
names are straight
forward.
Examples of unbranched
alkyl groups are methyl,
ethyl, propyl and butyl.

17. NOMENCLATURE OF ALKANES:
1. Find the longest continuous chain of
carbon atoms, and use the name
of this chain as the base name
2. Number the carbon atoms in the
longest chain, beginning with the
end nearest a substituent.
3. Name each substituent.
4. Begin the name with the number or
numbers of the carbon or carbons
to which each substituent is
bonded.
5. When two or more substituents are
present, list them in alphabetical
order.

18. EXERCISES:
1 Give the IUPAC name of the
following compound:
2. Write the structural formula of
A. 3-ethyl-2,2-dimethylpentane
B. 5-ethyl-2,6-dimethyloctane

19. Cyclo
alkanes
 Alkanes whose
carbon atoms
are joined in
rings are called
cycloalkanes.
 They have the
general
formula CnH2n.
 The simplest
cycloalkane is
cyclopropane.
cyclopropane cyclobutane cyclopentane
cyclohexane
C3H6 C4H8 C5H10 C6H12
Nomenclature of Cycloalkanes:
1. Cycloalkanes with one ring and no substituents:
2. Cycloalkanes with one ring and one substituent:

20. Cyclo
alkanes
3. Cycloalkanes with one ring and two or more substituents:
3. When a single ring system is attached to a single chain with a
greater number of carbon atoms, or when more than one ring
system is attached to a single chain, then it is appropriate to
name the compounds as cycloalkylalkanes.

21. Alkenes
Name Molecular
Formula
Boiling Point
Ethene (ethylene) C2H4 -102.4oC
Propene
(propylene)
C3H6 -48oC
1-butene C4H8 -6.47oC
cis-2-butene C4H8 4oC
Trans-2-butene C4H8 1oC
- are hydrocarbons that
contain at least one
carbon-carbon double
bond.
- are also called olefins.
- CnH2n
- are classified as
unsaturated
hydrocarbons
 In naming alkenes,
the –ene suffix
(ending) is used.
 The name of the
parent compound is
determined by the
number of carbon
atoms in the longest
chain.
Note that in butene, there are two molecules: one with the double bond in the first carbon, and the
other with the double bond in the second carbon. The numbers in the names refer to the lowest
numbered carbon atoms in the chain that is part of the CC double bond.

22. Geometric
Isomers of
Alkenes
 alkenes exhibit
geometric isomers.
 In the cis isomer, two
particular atoms or
group of atoms are
adjacent to each other
(same side of the
double bond).
 In the trans isomer, the
two groups are across
from each other.
 The cis and trans
isomers exhibit distinctly
different chemical and
physical properties.