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Introduction to Organic Chemistry
Writing Dot Lewis Structure with
multiple center atoms
Carbons will also be the center atom in
the organic molecule
◦ -C-C-C- chains
 Hydrogen is connected to carbon
unless it’s an oxyacids (HClO, etc..) or
Carbon has no more valence electrons
to share
 Order of increasing EN
◦ (least) C  N  O  F (most)


Write a Dot Lewis structure for
CH3COOH
Example

Write a Dot Lewis Structure for
CH3NH2
VSEPR Theory

VSEPR theory proposes that the
geometric arrangement of terminal
atoms, or groups of atoms about a
central atom in a covalent compound,
or charged ion, is determined solely by
the repulsions between electron pairs
present in the valence shell of the
central atom
VSEPR Thoery

Common shape and angles
◦ Linear (180o)
◦ Tetrahedral (109.5o)
◦ Trigonal planar (120o)

See table 1.2 page 5
Examples

Complete the following Dot Lewis
structure by adding the missing lonepair then predict the bond angles
a.
b.
c.
Elements in Organic Compounds
In organic molecules, carbon atoms
bond
• with four bonds.
• mostly with H and other C atoms.
• sometimes to O, N, S.
• sometimes to halogens F, Cl, and
Br.
• Table 1.3 page 7
9
Functional Groups
Functional groups are
• a characteristic feature of organic
molecules that behave in a
predictable way.
• composed of an atom or group of
atoms.
• groups that replace a hydrogen atom
in the corresponding alkane.
• a way to classify families of organic
compounds.
10
Alcohol

An alcohol
contains the
hydroxyl (-OH)
functional group.
R-OH
Writing structural formulas of
Alcohol
CH4O
Molecular
formula
CH3OH
Condensed
formula
Writing structural Formulas of
Alcohols

Draw Lewis structure and condensed
structural formulas for the four alcohol with
molecular formula C4H10O. Classify each
alcohol as primary, secondary or tertiary.
◦ Hints: Consider the connectivity of the four carbon atoms;
they can be bonded either four in a chain or three in a chain
with the fourth carbon as a branch on the middle carbon.
Then consider which carbon should connect to OH with
having the same molecule
Amines
In amines, the
functional group is
a nitrogen atom.
RNH2, R2NH or
R3H
|
—N —
Examples

Draw structural formulas of the
three secondary amines with the
molecular formula C4H11N
Carboxylic Acids
Carboxylic acids contain the
carboxyl group, which is a carbonyl
group attached to a hydroxyl group.
–COOH
O
║
— C—OH
Examples

Draw condensed structural
formulas for the two carboxylic
acids with molecular formula
C4H8O2
Carboxylic esters

An ester contains the carboxyl
group between carbon atoms.
–COOR or –CO2R
Examples

Draw structural formulas for the
four esters with the molecular
formula C4H8O2
Learning Check
Classify each of the following as: alcohol, ether,
aldehyde, ketone, carboxylic acid, ester, amine, or
amide.
1)
CH3─CH2─CH2─OH
2) CH3─O─CH2─CH3
3) CH3─CH2─NH2
O
║
4) CH3─C─OH
O
║
5) CH3─C─O─CH3
20
Examples

Consider the formula C4H8O2.
Write the structural formula for
this molecular formula with
◦
◦
◦
◦
A carboxyl group
Ketone group and a 2o alcohol group
An aldehyde and a 3o alcohol group
A carbon-carbon double bond and a
1o alcohol