Class Functional group/name Suffix Examples Formula
alkane C - C ane ethane CnH2n+2
alkene C = C Alkenyl ene ethene CnH2n
alkyne C ≡ C Alkynyl yne ethyne CnH2n-2
alcohol O-H Hydroxyl ol ethanol CnH2n+1OH
ether C – O - C Ether oxyalkane methoxymethane R –O -R
ketone O ‖ C – C - C
Carbonyl one propanone CnH2nO
or R-CO-R
aldehyde C = O ׀ H
Aldehyde anal ethanal CnH2nO
or R -CHO
Carboxylic acid O ‖ C – O H
Carboxyl oic acid ethanoic acid CnH2n+1COOH
ester O ‖ C – O –C
Ester oate ethyl ethanoate R – COO-R
amide CONH2 Amide anamide propanamide
amine NH2 Amine amine ethanamine
nitrile C ≡ N Nitrile nitrile propanenitrile
halogenoalkane F, Br, CI, I Halogeno chloroethane R - CI
Functional group
H H H H
׀ ׀ ׀ ׀
H - C – C – C – C – O-H
׀ ׀ ׀ ׀
H H H H
Hydrocarbon skeleton Functional gp
IUPAC nomenclature Systematic naming organic molecules
H CI O ‖ ׀ ׀
H - C – C – C - OH
׀ ׀ H H C1 – functional gp
C2 – substituent gp - CI
2 – chloropropanoic acid
Prefix Stem Suffix
Position and
substituent
Longest carbon
chain
Functional
gp
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3 2 1
H CH3 H H H
׀ ׀ ׀ ׀ ׀
H - C - C – C – C – C – H
׀ ׀ ׀ ׀ ׀
H H H H H
H H H H
׀ ׀ ׀ ׀
H - C – C – C – C – O-H
׀ ׀ ׀ ׀
H H H H
Hydrocarbon skeleton Functional gp
Hydrocarbon
Aliphatic Aromatic
Saturated Unsaturated
benzene alkylbenzene
H H
׀ ׀
H - C – C – H
׀ ׀
H H
H H
׀ ׀
C = C
׀ ׀
H H
Alkane Cycloalkane
Compound Ethane Ethanoic acid
Empirical formula CH3 CH2O
Molecular formula C2H6 C2H4O2
Full SF
Condensed SF CH3CH3 CH3COOH
Stereochemical formula
(3D)
H H
׀ ׀
H - C – C – H
׀ ׀
H H
H O
‖ ׀
H - C - C - OH
׀
H
Organic Chemistry
Cycloalkene Alkene
IUPAC nomenclature
Ring form
Functional group
Structural formula
2 – chloropropanoic acid
no aromatic ring
Systematic naming organic molecules
Prefix Stem Suffix
Position and
substituent
Longest carbon
chain
Functional
gp
H CI O ‖ ׀ ׀
H - C – C – C - OH
׀ ׀ H H C1 – functional gp
C2 – substituent gp - CI
CH3(CH2)3CH3
H H H H H
׀ ׀ ׀ ׀ ׀
H - C - C – C – C – C – H
׀ ׀ ׀ ׀ ׀
H H H H H
Use of parenthesis
Repeat CH2 x 3
CH3CH(CH3)(CH2)2CH3
Repeat CH2 x 2 CH3 branch
H CH3 H CH3 H
׀ ׀ ׀ ׀ ׀
H - C - C – C – C – C – H
׀ ׀ ׀ ׀ ׀
H H H H H
CH3CH(CH3)CH2CH(CH3)CH3
CH3 branch
3 2 1
benzene ring
inside
Isomerism Molecules with same molecular formula but diff arrangement of atom
Two types of Isomerism
Positional Chain Isomer Functional Gp Isomer
C – C – C – C – OH
C4H10O1
Structural Isomerism
• Same molecular formula • Diff structural formula • Diff arrangement of atom
Diff hydrocarbon chain skeleton
• Same molecular formula • Same structural formula • Diff spatial arrangement of atom
Stereoisomerism
Hydrocarbon Chain Isomer
Diff functional gp position Diff functional gp
C – C – C – OH
׀
CH3
C – C – C –C
׀
OH
C – C – C – C
׀
OH
C – C – C – C
׀
OH
C – C – C – O – C
Optical Isomer Geometric Isomer
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Compound Ethane Ethanoic acid
Empirical formula CH3 CH2O
Molecular formula C2H6 C2H4O2
Full SF
Condensed SF CH3CH3 CH3COOH
Stereochemical formula
(3D)
Isomer Physical property
Chemical property
Structural isomer - Hydrocarbon chain - Functional gp position - Functional gp
Different Different Different
Similar Similar
Different
Geometrical isomer Different Similar
Optical isomer Similar Similar
H H
׀ ׀
H - C – C – H
׀ ׀
H H
H O
‖ ׀
H - C - C - OH
׀
H
Structural formula – arrangement atoms in molecule (2/3D)
H H
׀ ׀
H - C – C – H
׀ ׀
H H
CH3CH3
ethane
Display full SF Condensed SF Ball/stick model Spacefilling
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Diff functional gp position
C4H9OH
Structural Isomerism
• Same molecular formula • Diff structural formula
• Diff arrangement of atom
Diff hydrocarbon chain skeleton
Diff functional gp position
Diff functional gp
CH3-CH2-CH2-CH3 ׀
OH
Butan–1-ol
CH3-CH-CH2-OH ׀
CH3
2-Methylpropan-1-ol
CH3 ׀
CH3-C-OH
׀
CH3
CH3-CH2-CH-CH3 ׀
OH
2-Methylpropan-2-ol Butan-2-ol
CH3-CH2-CH2-O-CH3
Methoxypropane
CH3-CH2-O-CH2-CH3
Ethoxyethane
7 structural isomers
CH3-CH-O-CH3
׀
CH3
CH3-CH2-CH2=CH2
C4H8
CH3-CH=CH-CH3 CH3-C=CH2
׀
CH3
CH2 – CH2
׀ ׀ CH2 - CH2
C4H9Br
CH3-CH2-CH2-CH2
׀
Br
CH3-CH2-CH-CH3
׀
Br
CH3 ׀
CH3-C-Br
׀
CH3
CH3- CH-CH2
׀ ׀
CH3 Br
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C6H14
CH3-CH2-CH2-CH2-CH2-CH3 CH3-CH-CH2-CH2-CH3
׀
CH3
CH3-CH2-CH-CH2-CH3
׀
CH3
CH3
׀
CH3-C-CH2-CH3
׀
CH3
CH3- CH- CH-CH3
׀ ׀
CH3 CH3
Diff hydrocarbon chain skeleton
Diff functional gp position
Diff functional gp Diff hydrocarbon
chain skeleton
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4 structural isomers 4 structural isomers
5 structural isomers
Diff hydrocarbon chain skeleton
Structural Isomerism
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C3H6O
H
׀
CH3-CH2-C=O
O
‖
CH3-C-CH3
OH
׀
CH3-CH=C-H
OH
׀
CH2=CH-CH2 CH3-O-CH=CH2
C4H8O
CH3-CH2-CH2-C-H ‖
O
CH3 -CH2 -C-CH3
‖
O
CH3-CH - C-H ‖ ׀
CH3 O
CH2=CH-CH2-CH2-OH CH3-CH=CH-CH2-OH CH3-CH2-CH=CH-OH CH3-CH2-O-CH=CH2 CH3-CH=CH-O-CH3
C5H10
CH2=CH-CH2-CH2-CH3 CH3-CH=CH-CH2-CH3 CH2=C-CH2-CH3
׀
CH3
CH2=CH-CH-CH3
׀ CH3
CH3-CH=C-CH3
׀
CH3
CH2-CH-CH2-CH3
CH2
CH3-CH-CH-CH3
CH2
CH3
׀
CH2– C-CH3
CH2
CH2
CH2 CH2 ּו
׀ ׀ CH2 –CH2
CH2 –CH-CH3
׀ ׀
CH2– CH2
Aldehyde Ketone Alkene/Alcohol Alkene/Alcohol Alkene/Ether
5 structural isomers
8 structural isomers
10 structural isomers
Cyclo – ring structure
• Same molecular formula • Diff structural formula
• Diff arrangement of atom
C5H11Br
Structural Isomerism
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CH3-CH2-CH2-CH2-CH2-Br CH3-CH2-CH2-CH-CH3
׀
Br
CH3-CH2-CH-CH2-CH3
׀
Br
CH3-CH-CH2-CH2-Br
׀
CH3
CH3-CH2-CH-CH2-Br
׀
CH3
CH3
׀
CH3–CH–CH-CH3
׀ Br
CH3
׀
CH3-CH2- C-CH3
׀ Br
CH3
׀
CH3-C-CH2-Br
׀ CH3
CH3- CH- CH-Br
׀ ׀
CH3 CH3
CH3 CH3
׀ ׀
CH3- C - CH2
׀ Br
CH3
׀
CH3-CH2- C-Br
׀ CH3
C3H6O2
CH3-CH2-C-OH
‖
O
CH3 - C- O-CH3
‖
O
H- C-O-CH2-CH3
‖
O
CH2- CH = CH
׀ ׀
OH OH
CH=C-CH3
Ι Ι
OH OH
HO-C=CH-CH3
׀
OH
HO-CH-CH=CH2
׀
OH
OH
׀
CH3-CH–C-H
‖
O
CH2- C = CH2
׀ ׀
OH OH
OH
׀
CH2-CH2-CH
‖
O
CH3-O-CH2-CH
‖
O
CH2 = C-O-CH3
׀
OH
CH2= CH-O-CH2
׀
OH
CH=CH-O-CH3
׀
OH
2-bromo-3-methylbutane 2-bromo-2-methylbutane
8 structural isomers
Alcohol / Alkene
Carboxylic acid Ester Aldehyde / Alcohol
Alcohol / Alkene / Ether
14 structural isomers
• Same molecular formula • Diff structural formula
• Diff arrangement of atom
H H H H H
׀ ׀ ׀ ׀ ׀
H - C – C – C - C – C – F
׀ ׀ ׀ ׀ ׀
H CH3 H H H
H CH3 ׀ ׀
CI – C – C – C
׀ ׀
H CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – Br
׀ ׀ ׀
H CH3 H
H CH3 H H
׀ ׀ ׀ ׀
H - C – C – C - C – H
׀ ׀ ׀ ׀
I H H H
H C
׀ ׀
C – C – C – C - C
׀
CI
C CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
CI H H
CH3 ׀
CI – C – C – C
׀
H
H H CI
׀ ׀ ׀
H - C – C - C – H
׀ ׀ ׀
H CH3 H
Halogenoalkane and Nomenclature
H
׀
CH3 – C – CI
׀
H
Types of halogenoalkane
Primary 1 0
NO alkyl /1 alkyl/R gp bond to C attach to halogen
H CH3 H
׀ ׀ ׀
H - C – C – C – CI
׀ ׀ ׀
H CH3 H
H
׀
H - C – CI
׀
H
Secondary 2 0
2 alkyl/R gp bond to C attach to halogen
H
׀
CH3 – C – CI
׀
CH3
H H H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H CI H
H
׀
R – C – CI
׀
R
Tertiary 3 0
3 alkyl/R gp bond to C attach to halogen
CH3
׀
CH3 – C – CI
׀
CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H CI H
R
׀
R – C – CI
׀
R
H H H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H CI H
H CH3 H
׀ ׀ ׀
H - C – C – C – C
׀ ׀ ׀
H CI H
CH3
׀
CH3 – C – CI
׀
CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H Br H
C ׀
CI – C – C – C
׀
C – C
Br CH3
׀ ׀
C – C – C – C – C
׀ ׀
CH3 CH3
C CI C
׀ ׀ ׀
C – C – C – C – C
׀
C
Primary 1 o
Secondary 2 o
Tertiary 3 o
H H H
׀ ׀ ׀
H - C – C - C – H
׀ ׀ ׀
H H F
H H CH3 H H
׀ ׀ ׀ ׀ ׀
H – C – C - C – C – C - H
׀ ׀ ׀ ׀ ׀
H CI CH3 H H
H
׀
CH3 – C – CI
׀
CH3
C ׀
HO – C – C – C
׀
C – C
H CH3 ׀ ׀
HO – C – C – C
׀ ׀
H CH3
H H H H H
׀ ׀ ׀ ׀ ׀
H - C – C – C - C – C – OH
׀ ׀ ׀ ׀ ׀
H CH3 H H H
H CH3 H
׀ ׀ ׀
H - C – C – C – OH
׀ ׀ ׀
H CH3 H
H CH3 H H
׀ ׀ ׀ ׀
H - C – C – C - C – H
׀ ׀ ׀ ׀
OH H H H
H C
׀ ׀
C – C – C – C - C
׀
OH
C CH3
׀ ׀
H - C – C – C – H
׀ ׀ ׀
OH H H
CH3 ׀
HO – C – C – C
׀
H
H H OH
׀ ׀ ׀
H - C – C - C – H
׀ ׀ ׀
H CH3 H
Alcohol and Nomenclature
H
׀
CH3 – C – OH
׀
H
Types of alcohol
Primary 1 0
NO alkyl /1 alkyl/R gp bond to C attach to OH
H CH3 H
׀ ׀ ׀
H - C – C – C – OH
׀ ׀ ׀
H CH3 H
H
׀
H - C – OH
׀
H
Secondary 2 0
2 alkyl/R gp bond to C attach to OH
H
׀
CH3 – C – OH
׀
CH3
H H H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H OH H
H
׀
R – C – OH
׀
R
Tertiary 3 0
3 alkyl/R gp bond to C attach to OH
CH3
׀
CH3 – C – OH
׀
CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H OH H
R
׀
R – C – OH
׀
R
H H H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H OH H
H CH3 H
׀ ׀ ׀
H - C – C – C – C
׀ ׀ ׀
H OH H
CH3
׀
CH3 – C – OH
׀
CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H OH H
OH CH3
׀ ׀
C – C – C – C – C
׀ ׀
CH3 CH3
C OH C
׀ ׀ ׀
C – C – C – C – C
׀
C
Primary 1 o
Secondary 2 o
Tertiary 3 o
H H H
׀ ׀ ׀
H - C – C - C – H
׀ ׀ ׀
H H OH
H H CH3 H H
׀ ׀ ׀ ׀ ׀
H – C – C - C – C – C - H
׀ ׀ ׀ ׀ ׀
H OH CH3 H H
H
׀
CH3 – C – OH
׀
CH3
H H H H H
׀ ׀ ׀ ׀ ׀
H - C – C – C - C – C –NH2
׀ ׀ ׀ ׀ ׀
H CH3 H H H
H CH3 ׀ ׀
NH2 – C – C – C
׀ ׀
H CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – NH2
׀ ׀ ׀
H CH3 H
H CH3 H H
׀ ׀ ׀ ׀
H - C – C – C - C – H
׀ ׀ ׀ ׀
NH2 H H H
H C
׀ ׀
C – C – C – C - C
׀
NH2
C CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
NH2 H H
C ׀
NH2 – C – C – C
׀
H
H H NH2
׀ ׀ ׀
H - C – C - C – H
׀ ׀ ׀
H CH3 H
Amines and Nomenclature
H
׀
CH3 – C – NH2
׀
H
Types of amines
Primary 1 0
NO alkyl /1 alkyl/R gp bond to C attach to nitrogen
H CH3 H
׀ ׀ ׀
H - C – C – C – NH2
׀ ׀ ׀
H CH3 H
H
׀
H - C – NH2
׀
H
Secondary 2 0
2 alkyl/R gp bond to C attach to nitrogen
H
׀
CH3 – C – NH2
׀
CH3
H H H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H NH2 H
H
׀
R – C – NH2
׀
R
Tertiary 3 0
3 alkyl/R gp bond to C attach to nitrogen
CH3
׀
CH3 – C – NH2
׀
CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H NH2 H
R
׀
R – C – NH2
׀
R
H H H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H NH2 H
H CH3 H
׀ ׀ ׀
H - C – C – C – C
׀ ׀ ׀
H NH2 H
CH3
׀
CH3 – C – NH2
׀
CH3
H CH3 H
׀ ׀ ׀
H - C – C – C – H
׀ ׀ ׀
H NH2 H
C ׀
NH2 – C – C – C
׀
C – C
NH2 CH3
׀ ׀
C – C – C – C – C
׀ ׀
CH3 CH3
C NH2 C
׀ ׀ ׀
C – C – C – C – C
׀
C
Primary 1 o
Secondary 2 o
Tertiary 3 o
H H H
׀ ׀ ׀
H - C – C - C – H
׀ ׀ ׀
H H NH2
H H CH3 H H
׀ ׀ ׀ ׀ ׀
H – C – C - C – C – C - H
׀ ׀ ׀ ׀ ׀
H NH2 CH3 H H
H
׀
CH3 – C – NH2
׀
CH3
Delocalization of electrons
Resonance • Describing delocalization of electrons within a molecule/polyatomic ion where bonding cannot be express by ONE single Lewis structure • Delocalization of π bond – π electrons spread over more than 2 nuclei • π electrons are shared/spread – more stable
Resonance structures benzene
Benzene 6HC6
resonance structure 1 resonance structure 2
Resonance hybrid
• All bonds C6H6 are identical in length/ strength • Hybrid of 2 resonance structures • No C-C (single) or C=C (double) bonds found • Only C ----- C bond • Intermediate character bet single/double bond
• Bond Order =
• Unhybridised p orbital • Delocalization electrons above below plane • sp2 hybridization on carbon center
1.5
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Delocalized electrons
Kekulé structure
Cyclohexa- 1,3,5 triene
χ ✓ double/single bonds bet them
Benzene
Hexagonal, planar
Resonance Hybrid more stable than any of the resonance structure ✓
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Kekule
✓
or
Resonance/Delocalization Energy
ΔH cyclohexene = -120 kJmol-1
ΔH cyclohexa1,3,5 triene = - 360 kJmol-1
ΔH Benzene = - 208kJmol-1
Enthalpy change hydrogenation
χ
- Benzene lower in energy by 152 kJ - More stable due to delocalization of π electrons
- 152 kJ
- 152
C-C Single bond
C = C Double bond
C = C Benzene
Bond length/pm 154 134 140
Bond enthalpy/kJmol-1
346 614 507
Evidence for Benzene structure
1
2
Click here evidence against Kekule
• X ray hit benzene crystal • Interact with electron (electron density map) • X ray diffraction produced • Bond length measured
X ray crystallography
NO single/double bond detected ✓
✓
3 No addition rxn in benzene C=C
Addition rxn
Substitution rxn
NO double bond
-240
……
-360
- 208
ΔH cyclohexa 1,3 diene = -240 kJmol-1
+
✓
✓
+ Br - Br → ✓