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Unit 1





Functional Groups
Depicting Structures of Organic Compounds
 Lewis Structures
 Condensed structural formulas
 Line angle drawings
 3-dimensional structures
Resonance Structures
Acid-Base Reactions
Curved Arrows
Classes of Organic Compounds

Organic compounds are commonly
classified and named based on the type
of functional group present.


An atom or group of atoms that
influences the way the molecule
functions and reacts.
The center of reactivity in an organic
compound
Classes of Organic Compounds

You must be able to recognize and draw
the functional groups listed in your
syllabus and on the following slides.
 Use the following slides and the tables
given in the front of your text and in
the chapter to learn these.
Functional Groups
Class of Compound
Functional Group
Alkane
None
Cycloalkane
None
Alkyl halide
C
X
Alkene
C
C
Alkyne
C
C
Alcohol
C
OH
Ether
C
O C
Functional Groups
Class of Compound
Aldehyde
Ketone
Carboxylic Acid
Acid Chloride
Ester
Functional Group
O
C
H
O
C
C
C
O
C
OH
O
C Cl
O
C
O
C
Functional Groups
Class of Compound
Amine
Amide
Nitrile
Aromatic ring
Functional Group
C
N
O
C
R
N
R'
R
C
R'
N
Alkanes



Contain C-C single bonds
 no functional group
Nonpolar covalent bonds
 electrons shared equally
Tetrahedral electron domain
geometry
H
H
H
H H H
H H H
H HCH CH
H C C C HC H
H C HC C H
H H H
H H
H H H
CH3CH2CH3
CH
CH
CH
CH
CH
CH
3
2
3
3
2
3
C C
H
H
C H
HH

H H H
sp3 hybridized carbons
H C C C H
H H H
CC
C
Cycloalkanes




Contain C – C with at least 3
of the carbons arranged in a
cyclic (ring) structure
 No functional group
Nonpolar
Tetrahedral
sp3 hybrid orbitals
CH3CH2CHCH2CH3
CH
H2C
CH2
H
H
H
H
c
c
c c
H
H
H
c
H
H
H
Alkenes



H
Contain C=C (carbon-carbon
double bonds)
 1 sigma bond & 1 pi bond
Non-polar
Trigonal planar geometry
Which atoms must
be coplanar in an
alkene?
H
H
C
C
HH
H
hybridized carbons
C
C
H
C
H
C
CH
H 3
H
CH2=CHCH3
H2C CHCH3
H
H
C H
H
 sp2
C
H
CH2=CHCH3
Alkenes


The C=C present in an alkene is composed
of 1 sigma (s) bond and 1 pi (p) bond.
A sigma (s) bond forms when two orbitals
overlap end to end.
 electron density is centered along the
internuclear axis
 cylindrically symmetrical
Internuclear axis
Alkenes

A pi (p) bond forms when two p orbitals
overlap side to side
 electron density is located above and
below the internuclear axis
 oriented parallel to the internuclear
axis
H
H
H
C C
H
H
H

H
H
C C
Alkenes
Hoccurs around single bonds.
H
Free rotation
H
H
H C C H
H
H
H
H
C C
H
H
H
H
H
 Double and triple bonds areHrigid.
 Cannot rotate freely.
H C C H
 Rotation would cause
H loss Hof overlap of the p
orbitals, destroying the p bond.
Alkynes
H
H
 Contain
C triple
H
H C C C CH
C C bonds
3
C C
H
C H
 1 sigma bond
2 pi bonds
H
Nonpolar
CH2=CHCH
C3
Linear electron domain
H
geometry
H
H
H


H
H

C
C
C
H
H
C
H C
C
C H
H
C
HC CCH3
H
H
C
C
CH2=CHCH3

C
sp hybridized carbons
C
H
H
H
C
Which atoms must
be co-linear in an
H
alkyne?
C
H
H
C
H
Aromatic RingC
H
H




CH
C
H
CCH CHCH
CC
3
H
3
H
C
H
C
H H C
Planar ring system with
C
C
H
alternating single and double C HCC C H H C C
H
Ph H
C
C
bonds
C
 does not react like an
CH CHCH
alkene
Nonpolar
CH3CHCH3
CH3CHCH3
C
Trigonal planar
C
C
Ph
2
sp hybridized carbons
C
C
C
Benzene ring is a very
H
PhC
common aromatic ring.
H
H
3

CC
Ph
3
Ph
C
C
C H
C
H
C
C
C
C
H
C
C
N
..
C
C
H
H
H
N
HH
H
C
C
C
C

C
H C
C
H C
CH
C3 C
Alkyl Halides
Contain
C-halogen
bond
H
H
H
F, CCl,C Br,H or I
H
HH
H
H
H
C
C H
H C C C
H
H
H
 Polar covalent
C-halogen bond
H
CH2=CHCH3
CH2=CHCHshared
 electrons
unequally
3

H H H H


H C C C C H
H H
H Br



C HCH3
C
C
C
H
CH
=CHCH3
H 2H
=CHCH3
2
CHCH
=CHCH
2
3
H H H H
H HH HH HH H
H C C CC CCC CC
H HC
H
H
H C C
H C CH CH
H Br
H HH H
H Br
H HBr
H
CH(Br)CH
CHCH
CH(Br)CH
CH2CH3
3
H H H H

H C C C C H
H Br- H H
3
Br-Br
 Br
-

CH(but
CH(Br)CH
CH3CH(Br)CH
Many
not 2CH
all)3 alkyl
halides 2CH3
3
Br molecules as well.
are polar
Br
2
3
CH3CH(Br)CH
-
+



Polar Covalent Bonds

Two ways to indicate bond polarity
 partial charges



- on more electronegative element
+ on less electronegative element
direction of dipole moment



+ on less electronegative element
arrow pointing toward more
electronegative element
Polar Covalent Bonds


Dipole moment:
A measure of the separation
and magnitude of the positive and negative
charges in polar bonds or polar molecules.
Important Polar Covalent Bonds:
C-O
C-N
O-H

N-H
C-halogen
H-halogen
Important Nonpolar Covalent Bonds:
C-C
C-H
halogen-halogen
Polar Molecules

Polar Molecule:

a molecule with a non-zero molecular
dipole moment


H
+
contains 1 or more polar covalent bonds
arranged asymmetrically within the
molecule


net negative end, net positive end
-
use molecular geometry to determine
polarity
exhibit dipole-dipole interactions

How does the BP of a polar molecule
compare to the BP of a nonpolar molecule
with similar molar mass?
O
H
+
Nonpolar Molecules

Nonpolar molecules:


a zero (or very small) molecular dipole
moment
contain either:



only nonpolar covalent bonds
2 or more polar covalent bonds arranged
symmetrically
London dispersion forces



found in all molecules
only IMF found in nonpolar molecules
strength increases as surface area
increases
– What variables make SA increase?
– What happens to the BP as SA ?
Polar/Nonpolar Molecules
Example: Which of the following are polar
molecules?
H
HBr
CCl4
Cl
C
Cl
H
H
Br
C C
Br
H
H
H
C C
Br
Br
CH3CH(OH)CH2CH(CH3)2
Alcohols



Contain C-O-H bond
 hydroxyl group
Polar covalent bonds
 C-O bond
 O-H bond
Polar molecule
 dipole-dipole interactions
 hydrogen bonding


CH3CH(OH)CH2CH(CH
H
H
H
H
O
C
C
H
H
C
H
H
H
H
C
C
C
H
OH H
CH CC
H
H
H
C
H
H
C
HH
H
H CH(CH
C H)
OH
CH CH(OH)CH
H
H
3
2
What causes hydrogen bonding?
H OH
How does hydrogen bonding
H O H H
affect BP?
H
C
C
C
C
H
3 2
H
C
H
CH CH(OH)CH CH(CH )
Ethers
H



3
O
2
O
3 2
H
H C C-O-C
Contain
bondH
C H
C
H
H C
H
Polar covalent
bonds C
H
tetrahedral e.d.
geometry
H ) HH
H H H CH(CH
CH3CH(OH)CH
2
3 2
CH
CH(OH)CH
CH(CH
)
3geo.
2
3 2
 bentCH
molecular
CHO
H
3
O
H
H
HH
H
C
C
C
H
O
C
O
HH
H
C
C
H
H
H
C
C
H
H
H
H
HH H
H
H
H C C O C C H
 Polar molecules
H C C OOHC C H
 dipole-dipoleH interactions
H
H H
H H
H H
H
H
H
C
H
H H
CH3CH2OCH2CH
O C C H
(CH
H2)2O
H3CH
H
CH3CH2OCH2CH3
CH3CH2OCH2CH3
OH
(CH3CH2)2O
(CH3CH2)2O
O



H
H
H
H C
C
C
H H
Amines
C
C
H
H H H H H
CH H
H H H H
H
H H H
H HC HC C HC C
HH HC C C C C N C H
N
H H H H H
Contain C-N-R
H C C C C C N C H
H H H H H
R’
HH H H H H H HH HH HH H
Polar covalent
CH3CHbonds
CH2CH2CH2NHCH3
2
CH3CH2CH2CH2CH
Polar molecules
CHCH
CH
CH2CH
CH2NHCH3
CH
CH
CH
3
2 CH
2 NHCH
H
 Dipole-dipole interactions
H
o
o
HH
 Hydrogen bonding
N (1 and 2 )
N
NN
Common organic bases
3


2
lone pair of e- on N
CH3NH2
o
1
primary
CH3NHCH3
o
2
secondary
(CH3)3N
o
3
tertiary
2
2
2
3
Aldehydes
H HO O
H HC C C CH H
H O
H H
C C H
O


Contain C - H (-CHO)
Carbonyl (C=O)



H
always on the 1st or last
carbon in a chain
trigonal planar geometry
sp2 hybrid orbitals
H O
H
C

Polar covalent bond

Polar molecule
C
H

H
dipole-dipole
interactions
H
CH3CHO O O
H H
O O
H
H
C
H
CH3CHO
CHO
CHCH
CHO
3
3
H
C
H
CH3C(O)CH
CH3C(O)CH3
Ketones
H
O




H
Contain C-C-C
Carbonyl attached to middle
of chain
O
H
C
C
C

Trigonal planar e.d. geo.

H C
sp2 hybridized
H
CH3CHO
H
H
C
H
Polar covalent bond
Polar molecule CH3C(O)CH3
 dipole-dipole interactions
H
C
H
O
H
C
H
H
C
O
H
C
C
H
H
H
H
CH3C(O)CH3
CH3CHO
CH3CHO
H OO
HO
HH
H
H H
H C CH C H
CH
O
H
C H
H
HH
H HC
H
H
C
C
HCH CHO
H
3
N
N
Carboxylic Acids
CH3NH
NHCH3 (CH
)3N 3)3N
CH2 3NHCH
3 CH3NHCH
3 (CH
2
3
H H O
1
2
3
1 group
2
carboxyl
H 3H HHO OH CO C C O
H
H
H C HC CC CO HCH HO H
-CO2-CO
H 2H -COOH
H C C C O H
-COOH
H H H H

Contain

Polar covalent bonds



o
o
o
o
o
H
H
CH3CH2CO2H
CH3CH2CH
CO32CH
H 2CO2H
Polar molecules
 dipole-dipole
 hydrogen bonding
trigonal planar
sp2 hybridized carbon
o
CH3CH2CO2H
OH
OH
O
H
HH
H
C
H
C
O
C
O
OH
OH
O
Acid Chloride


Contain
H
H C
Polar molecule
C C
H forces
 dipole-dipole
H C
C
C
planarH geo.
C


Lachrymators
H
C
C
H
C
Cl
O
H
Trigonal
sp2 hybridized C

O
C
C
Cl
H
H
H
O
H
C
O
C
Cl
CH3CHCH2CH2CH2CH3
Cl
H
H
C
H
C
C
OH
O
Esters
H O
HH HH OO
H HH H
H H
H
H CC CC C C OO C C C CH H
 Contain
H C C CH OH CO C HH H
HH HH
H HH H
-CO2R where R =Halkyl
group
HH C C HC HO C C H
H




CH3CHH
CO2H
CH2CH3
H H
2 CO
CH
CH
CH2CH3
bonds
3
2
2
CH3CH2CO2CH2CH3
Polar covalent
Polar molecules
CH3CH2CO2CH2CH3
HH
 dipole-dipole interactions
H
OH
H
H
H
H
HH
OO C H O
H H C
C C C OC
C H
H
H
HC
planarH
O H HC C
CH H O
C
H
O
H
H
CH C
H
C
trigonal
sp2 hybridized
H
HH
CO H H H
CH O
HO
C
CH C
H
O
HH
H
-CO2R where R = alkyl group
O
H
H
H O
C
C
H
H
C
H
H
N C C
Amides
H
H
H
H
H
H
H O
H O
H
H
H
H
H H O
N C C H
H HH C CH CC CC N
C C H
CH3CH2CONHCH2CH3
H
 where R and R’
C alkyl
C N C HHC HHH
H HH HH
H = CH or
H
N
H H
H H H
 Polar covalent bonds
CHCH
CH2CONHCH
CONHCH2CH
CH
CH
33
2
2 3 3
H
H
O
H
 Polar molecules
CH3CH2CONHCH2CH3
H
H
 dipole-dipole
C H
O
C interactions
H
H
C o and 2o)
HH
C
 hydrogenC bonding
(1
H
NH
H
H H
C H
O
C
H
H
O
H HH
H
H C C C OOC C H
H 2
H
H
 C=O is trigonal planar & sp hyrbridized
C
C
C
H
O
HH
H
H
C H
O
C
H
O
O
HH
C OH
C
CO
H
CH3CNH2
CH3HCNHCH
H3CN(CH3)2
O 3 HCH

Contain
1
o
o
2
-CO2R where R = alkyl group
o
3
-CO2R where R = alkyl group
H
H




H
H
H
Nitriles
CH3CH2CONHCH2CH3
Contain
H
Polar covalent
bond H
H
H
PolarHmolecule
C H
O
 dipole-dipole
C
H
C
C
C
H
Linear,Hsp hybridized
O
HH C
O
CH3CNH2
o
O
CH3CNH2
o
1
H
H
N
H C
O H
2
C
CH3CN
O
CH3CNHCH3
o
CH3CN
CH3CN(CH3)2
o
N
NH2
Functional Groups
HO2C
N groups
Example: Identify the functional
N
present in the following compounds.
O
C
H
O
OH
NH2
O
OH
C
H
HO2C
O
OH
testosterone
OCH3
Vanillin
N
N
H
O
C
O
Lisinopril
OH
Depicting Structures of Organic
Compounds

Organic compounds can be described using
a variety of formulas:







Empirical formula
Molecular formula
Lewis structure
Full structural formula
Three dimensional drawings
Condensed structural formula
Line angle drawings
Depicting Structures of Organic
Compounds

Ethyl acetate is an organic molecule with:


empirical formula = C2H4O
 lowest whole number ratio
molecular formula = C4H8O2
 actual number of each type of atom
present
Depicting Structures of Organic
Compounds

Ethyl acetate is an organic
molecule with:
 Lewis structure:


depicts all covalent bonds using
a straight line and shows all
nonbonding pairs of electrons
– What are covalent bonds?
. ..
.
H O
H
a Lewis structure without the
nonbonding electrons
C
H
. .
Full structural formula:

C
..
O
..
C
H
H
C
C
H
H
H
..
..
H O
H
H
C
O
H
H
C
C
H
H
H
Depicting Structures of Organic
Compounds

. .
acetate is
..
Ethyl
an organic
..
molecule with:
H H
H O
HH
 3-D drawing:
O
. .
H
H
H
O
C
C
O
C..
C H O CC C C H H
.. H
H
C
C H OH
H
H H H
H
C
C
H

Condensed structural formula

Line angle drawing
H
H H
CH3CO2CH2CH3
CH3CO2CH2CH3
O
..
O
Lewis Structures

Lewis structures are used to represent
the covalent bonds present in a molecule.



Symbol for each atom
Covalent bonds between atoms depicted
using a solid line
Unshared electrons are shown around
the appropriate atom
. ..
.
H O
H
C
H
C
..
O
..
H
H
C
C
H
H
H
Lewis Structures

To draw a Lewis structure:
 Count the number of valence electrons

For a cation (+), subtract 1 electron
for each positive charge
– NH4+ : 5 + 4 (1) -1 = 8 e-

For an anion (-), add 1 electron for
each negative charge
– CN- : 4 + 5 + 1 = 10 e-
Lewis Structures

Draw a skeleton structure showing the
chemical symbol for each atom. Connect the
appropriate atoms using a single bond.

Skeletons for organic compounds:




The backbone generally contains C-C bonds
N,O, and S can either be part of the
backbone or attached to one of the carbons
as a substituent.
H will be attached to C,N,S and/or O
Halogens will be attached to C as
substituents.
Lewis Structures

Add pairs of electrons to the atoms giving
each one an octet



H only gets 2 electrons
Try filling the octets of N, O, S, and
halogens first
There will generally NOT be any “leftover”
electrons for organic compounds.

Organic ions, however, may have leftover
electrons.
 Put them on an atom that needs an octet.
Lewis Structures

If there are not enough electrons to give
all atoms an octet, share electrons to form
multiple bonds.



Single bond:
 one pair of electrons shared
H Cl
double bond:
 two pairs of electrons shared
O C O
triple bond:
 three pairs of electrons shared N
N
O
O
O
OO
Lewis Structures
O
O
CH
CO
CH
CHCH
CH3CO
CH
CH
CH
CO
CH2CH3
2 CO
2 CH
2 3 CH
2 CH
3 CO
33 CH
2
CH
O
OO
Common neutral bonding patterns
3 3
C
C
total
bonds
lone
pairs
2 2
2 2
3 3
...
.
.
.
CN
. .. H N
H.H
C . CN .HNN
O
..
.. ....
..
.
O
O
H
.
Br
O
.. ....
..
......
...
.
. .
O
Br
..Br
....Br
..
C
N
O
H
Halogens
4
3
2
1
1
0
1
2
0
3
.
B
.
Lewis Structures
Example: Draw the Lewis structure for C2H3I.
Lewis Structures
Example: Draw the Lewis structure for a
ketone with the molecular formula, C5H9BrO.
Lewis Structures
Example: Draw two possible Lewis structures
for CH2COCH3-.
These two Lewis structures are
resonance structures.
Formal Charge


Which atom in each of the previous Lewis
structures is negatively charged?
Formal charge provides a method for
keeping track of electrons in a compound.


determines which atom(s) in a structure
bear(s) the charge in a polyatomic ion
identifies charged atoms within a molecule
that is neutral overall.
.
.
.
Formal Charge

Formal charge:

-
a calculated value that compares
the number
.
. .
.
.
.
of valence .electrons
for Oa.. particular atom to
H
the number of electrons
to that
C C assigned
H
C
atom in a Lewis structure
H
H

H
FC = group # - nonbonding e- - 1/2 (bonding e-)
H
H
.. .
.O .
.
C
C
H
C
H
H
FC = 6
-6
-1/2(2)
-1
Formal Charge
Common Organic Bonding Patterns and Formal
Charges:
Positive
Neutral
C
C+
C
N
N+
N
O
O+
O
Negative
C
-
-
N
O
-
Formal Charge
Example: Calculate or determine the
formal charge on N and O in (CH3)3NO.
All Lewis structures you draw from now on should
include any non-zero formal charges that are present.