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1-1CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Chapter 12. Saturated Hydrocarbons
SectionsSections
1-2CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
12.1 Organic and Inorganic Compounds12.1 Organic and Inorganic Compounds12.2 Bonding Characteristics of the Carbon Atom12.2 Bonding Characteristics of the Carbon Atom12.3 Hydrocarbons and Hydrocarbon Derivatives12.3 Hydrocarbons and Hydrocarbon Derivatives12.4 Alkanes: Acyclic Saturated Hydrocarbons12.4 Alkanes: Acyclic Saturated Hydrocarbons12.5 Structural Formulas12.5 Structural Formulas12.6 Alkane Isomerism12.6 Alkane Isomerism12.7 Conformations of Alkanes12.7 Conformations of Alkanes12.8 IUPAC Nomenclature for Alkanes12.8 IUPAC Nomenclature for Alkanes12.9 Line-Angle Formulas for Alkanes12.9 Line-Angle Formulas for Alkanes12.10 Classification of Carbon Atoms12.10 Classification of Carbon Atoms12.11 Branched-Chain Alkyl Groups12.11 Branched-Chain Alkyl Groups12.12 Cycloalkanes12.12 Cycloalkanes12.13 IUPAC Nomenclature for Cycloalkanes12.13 IUPAC Nomenclature for Cycloalkanes12.14 Isomerism in Cycloalkanes12.14 Isomerism in Cycloalkanes12.15 Sources of Alkanes and Cycloalkanes12.15 Sources of Alkanes and Cycloalkanes12.16 Physical Properties of Alkanes and Cycloalkanes12.16 Physical Properties of Alkanes and Cycloalkanes12.17 Chemical Properties of Alkanes and Cycloalkanes12.17 Chemical Properties of Alkanes and CycloalkanesChemistry at a Glance: Properties of Alkanes and Chemistry at a Glance: Properties of Alkanes and Cycloalkanes Cycloalkanes
1-3CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
IntroductionIntroduction
Organic chemistryOrganic chemistry is the study of the compounds of is the study of the compounds of carbon atoms consisting of single, double, and carbon atoms consisting of single, double, and triple covalent bonds with C, H, O, N, and some triple covalent bonds with C, H, O, N, and some metalsmetals
BiochemistryBiochemistry is the study of the compounds of is the study of the compounds of carbon atoms consisting of single, double, and carbon atoms consisting of single, double, and triple covalent bonds with C, H, O, N, and some triple covalent bonds with C, H, O, N, and some metalsmetals
1-4CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
12.1 Organic and Inorganic Compounds12.1 Organic and Inorganic Compounds
1-5CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
SectionsSectionsChapter 1: Covalent Bonding and Shapes of MoleculesChapter 1: Covalent Bonding and Shapes of Molecules
1.1. IntroductionIntroduction
2.2. Electronic Structure of atomsElectronic Structure of atoms
3.3. Lewis Model of bondingLewis Model of bonding
4.4. Bond angles and molecular shapesBond angles and molecular shapes
5.5. Polar and non-polar moleculesPolar and non-polar molecules
6.6. ResonanceResonance
7.7. Orbital overlap of covalent bondingOrbital overlap of covalent bonding
8.8. Functional groupsFunctional groups
1-6CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
IntroductionIntroduction
Organic chemistryOrganic chemistry is the study of the compounds of is the study of the compounds of carbon. carbon.
C is a small atomC is a small atom • it forms four bonds consisting of single, double, it forms four bonds consisting of single, double,
and triple bondsand triple bonds• it forms strong bonds with C, H, O, N, and some it forms strong bonds with C, H, O, N, and some
metalsmetals
ProblemProblem: Identify : Identify organicorganic and and inorganicinorganic compounds:compounds:
NaCl, CNaCl, C22HH55OH, CHOH, CH33COOH, NaCOOH, Na22COCO33, CH, CH33OK, KOHOK, KOH
1-7CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Atomic OrbitalsAtomic Orbitals
s orbitals orbital - a spherical-shaped atomic orbital; can - a spherical-shaped atomic orbital; can hold a maximum of 2 electronshold a maximum of 2 electrons
p orbitalp orbital - a dumbbell-shaped atomic orbital; the - a dumbbell-shaped atomic orbital; the three p orbitals (pthree p orbitals (pxx, p, pyy, p, pzz) can hold a maximum ) can hold a maximum of 2 electrons eachof 2 electrons each
Electrons always fill starting with the lowest-energy Electrons always fill starting with the lowest-energy orbital:orbital:
lower energylower energy higher energyhigher energy1s1s22 2s2s22 2p2p66 3s3s22 3p3p66
We will be concerned with only the valence We will be concerned with only the valence electrons which are the outermost electrons electrons which are the outermost electrons involved in forming bonds. involved in forming bonds.
1-8CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Shapes of s Atomic OrbitalsShapes of s Atomic OrbitalsAll All ss orbitals have the shape of a sphere, with orbitals have the shape of a sphere, with
its center at the nucleus its center at the nucleus • of the s orbitals, a 1s orbital is the smallest, a 2s
orbital is larger, and a 3s orbital is larger still
1-9CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Shapes of p Atomic OrbitalsShapes of p Atomic Orbitals• A p orbital consists of two lobes arranged in a
straight line with the center at the nucleus
1-10CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Electronic Structure of atoms (Review)Electronic Structure of atoms (Review)Ground state electronic configuration of atoms in core formatGround state electronic configuration of atoms in core format
Carbon (C): ):Carbon (C): ): [He] [He] 22ss22, 2, 2pp2 2
oror [He][He] 2 2ss22, 2p, 2pxx113p3pyy
113p3pzz00
Potassium (K): Potassium (K): {Ar] {Ar] 44ss11
Phosphorous (P):Phosphorous (P): [Ne] [Ne] 33ss22, 3, 3pp33
Valence shell electronic configurationValence shell electronic configuration
Carbon (C): ):Carbon (C): ): 33ss22, 3, 3pp22
Potassium (K): Potassium (K): 44ss11
Phosphorous (P):Phosphorous (P): 33ss22, 3, 3pp33
How you get the electronic configuration of an atom from the How you get the electronic configuration of an atom from the periodic table?periodic table?
1-11CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Excited State Valence Electron ConfigurationExcited State Valence Electron Configuration
Carbon (C):Carbon (C):
Ground state:Ground state: 22ss22, 2, 2pp2 2 or or 22ss22, 2p, 2pxx113p3pyy
113p3pzz00
Excited State:Excited State: 22ss11, 2, 2pp3 3 or or 22ss11, 2p, 2pxx113p3pyy
113p3pzz11
1s2 2s2 2p2
E
1s2 2s1 2p3
electronpromotion
1-12CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Lewis Model of bonding (Review)Lewis Model of bonding (Review)
"octet rule“"octet rule“atoms tend to gain, lose or share electrons so as to atoms tend to gain, lose or share electrons so as to
have eight electrons in their outer electron shell have eight electrons in their outer electron shell ““Lewis structure of atoms”Lewis structure of atoms” Shows only valence electrons, is a convenient way Shows only valence electrons, is a convenient way
of representing atoms to show their chemical of representing atoms to show their chemical bonding pattern. bonding pattern.
1-13CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Lewis structure of atoms (Review)Lewis structure of atoms (Review)
1-14CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
CC
NN
NaNa++
OO
Cations•What elements lose electrons? And how many?•What is the positive charge on their cations?•Anions•What elements gain electrons?•What is the positive charge on their anions?•Covalent bonds•How many covalent bonds are formed? •What elements share electrons?
Cations and AnionsCations and Anions
1-15CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Covalent or IonicCovalent or IonicIdentify Identify covalent covalent and and ionicionic compounds: compounds:
NaCl, CNaCl, C22HH55OH, CHOH, CH33COOH, NaCOOH, Na22COCO33, CH, CH33OK, KOHOK, KOH
Covalent :Covalent :
Ionic:Ionic:
1-16CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Ionic model of bonding modelIonic model of bonding model (Review)(Review)
+ -Na + F Na F
Ionic bondIonic bond - results from the - results from the electrostatic attractionelectrostatic attraction
between a cation and an anion of two atoms typically between a cation and an anion of two atoms typically
involves a involves a metalmetal and a and a nonmetallic element.nonmetallic element.
Anion:Anion: An atom that gains electrons becomes a negative
ion
CationCation: An atom that loses electrons becomes a positive
ion
+ 2-Li + S 2 Li S2
1-17CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Covalent model of bondingCovalent model of bonding (Review)(Review)
Covalent bondsCovalent bonds - results from the sharing of electrons - results from the sharing of electrons between two atoms typically involves two between two atoms typically involves two nonmetallic elementsnonmetallic elements
1-18CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
HH
2.12.1
LiLi Be Be BB CC NN OO FF
1.01.0 1.51.5 2.02.0 2.52.5 3.03.0 3.53.54.04.0
NaNa MgMg AlAl SiSi PP SS ClCl
0.90.9 1.21.2 1.51.5 1.81.8 2.12.1 2.52.53.03.0
increases
increases
Is the attraction of an atom for its valence electronsIs the attraction of an atom for its valence electrons
Electronegativity (Review)Electronegativity (Review)
1-19CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Nonpolar/polar-covalent and ionic bonds. (Review)Nonpolar/polar-covalent and ionic bonds. (Review)
We classify chemical bonds as We classify chemical bonds as polar polar covalent, nonpolar covalent, nonpolar covalentcovalent and and ionicionic based on the difference in based on the difference in electronegativity between the atomselectronegativity between the atoms
Difference in ElectronegativityBetween Bonded Atoms Type of Bond
less than 0.5
0.5 to 1.9greater than 1.9
nonpolar covalentpolar covalent
ionic
1-20CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Classify following bonds nonpolar-covalent, Classify following bonds nonpolar-covalent, polar-covalent or ionic bonds polar-covalent or ionic bonds
N-H N-H nonpolar-covalent, polar-covalent or ionic bondsnonpolar-covalent, polar-covalent or ionic bonds
O-H O-H nonpolar-covalent, polar-covalent or ionic bondsnonpolar-covalent, polar-covalent or ionic bonds
C-H C-H nonpolar-covalent, polar-covalent or ionic bondsnonpolar-covalent, polar-covalent or ionic bonds
C-F C-F nonpolar-covalent, polar-covalent or ionic bondsnonpolar-covalent, polar-covalent or ionic bonds
Na-Cl Na-Cl nonpolar-covalent, polar-covalent or ionic bondsnonpolar-covalent, polar-covalent or ionic bonds
Al-Cl Al-Cl nonpolar-covalent, polar-covalent or ionic bondsnonpolar-covalent, polar-covalent or ionic bonds
1-21CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Drawing Lewis structure molecules and ionsDrawing Lewis structure molecules and ions (Review)(Review) 1)1) Predict arrangement of atoms.Predict arrangement of atoms.
a) H is always a terminal atom.
b) Halogens and oxygen are often terminal.
c) The central atom of binary compounds is usually written
d) first and has the lowest subscript.
e) Most organic compounds have more than two central atoms.
f) These are mainly C, but N, O and S can also be central atoms.
2) 2) TotalTotal number of valence electrons (e-) number of valence electrons (e-)
a) Add all valence electron of atoms in the molecule from the formula.
b) Add the ion charge for negative ions or subtract for positive ions.
1-22CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Drawing Lewis structure molecules and ions Drawing Lewis structure molecules and ions (Review)(Review) 3)3) Draw the skeletal structure by connecting the atoms with Draw the skeletal structure by connecting the atoms with
single bonds.single bonds.
4) 4) Give each of the atoms an octet (8 e-). Adding unshared Give each of the atoms an octet (8 e-). Adding unshared pairs of electronspairs of electrons
5) 5) Count the total number of e- used through step 4 and Count the total number of e- used through step 4 and compare to the number calculated incompare to the number calculated in step 2. step 2.
a)a) If it results in zero, the structure is correct. If it results in zero, the structure is correct.
b)b) For every two electrons too many, another bond is added For every two electrons too many, another bond is added (minimize formal charges). (minimize formal charges).
Multiple bonds form only with C, N, O and S.Multiple bonds form only with C, N, O and S.
Total number of bonds to neutral atoms:Total number of bonds to neutral atoms: 4 bonds to C 3 bonds to N, P 2 bonds to O, S 1 bond to H, F, Cl, Br, I
1-23CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Calculation of formal charges of atoms in the Lewis structureCalculation of formal charges of atoms in the Lewis structure
1.1. For a neutral molecule, the sum of the formal charges equals zero. For For a neutral molecule, the sum of the formal charges equals zero. For
a polyatomic ion, the sum of the formal charges equals the charge on a polyatomic ion, the sum of the formal charges equals the charge on
the ion.the ion.
2.2. Formal charge of each atom is calculated by:Formal charge of each atom is calculated by:
(group #) - (# unshared e-) - (group #) - (# unshared e-) - ½½ (# shared e-) (# shared e-)
3.3. Formal charges are shown as + or - on the atom with that charge.Formal charges are shown as + or - on the atom with that charge.
4.4. An atom with the same number of bonds as its group number has no An atom with the same number of bonds as its group number has no
formal charge.formal charge.
5.5. In a molecule if two different elements can be assigned a negative In a molecule if two different elements can be assigned a negative
charge, then the more electronegative element gets the charge; the charge, then the more electronegative element gets the charge; the
same sign should not be given to bonded atoms.same sign should not be given to bonded atoms.
1-24CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Types of electronsTypes of electrons
Bonding pairsBonding pairsTwo electrons that are Two electrons that are sharedshared between two atoms. between two atoms. A covalent bond.A covalent bond.
Unshared (nonbonding ) pairsUnshared (nonbonding ) pairs A pair of electrons that are not shared between two A pair of electrons that are not shared between two
atoms. atoms. Lone pairsLone pairs or nonbonding electrons. or nonbonding electrons.
H Cloo
oo
oooo
Bonding pair
Unsharedpair
1-25CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Lewis StructuresLewis Structures (Review)(Review)
Hydrogen chloride
Methane Ammonia
Water
H O
H
H
H NH C
H
H
H Cl
H
H
H2O (8)
NH3 (8)CH4 (8)
HCl (8)
•How many bonding electron pairs are in the molecule?
•How many bonding electron pairs are in each atom?
•How many nonbonding electron pairs are in the molecule?
1-26CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Draw Lewis structure of moleculesDraw Lewis structure of molecules
CHClCHCl33
CC22HH44
CC33HH88OO
CHCH33CHCH22CHCH22OHOH
CHCH33CHCH22OCHOCH33
CHCH33COCO22HH
CHCH33CHOCHO
1-27CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Draw Lewis structure and assign formal chargesDraw Lewis structure and assign formal charges
CHCH33NHNH33++
CHCH33OO--
C N
H
H
H
H
H
H
+
1-28CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
VValence-alence-SShell hell EElectron-lectron-PPair air RRepulsion epulsion (VSEPR) model(VSEPR) model (Review)(Review)
For predicting shapes of molecules and polyatomic Ions For predicting shapes of molecules and polyatomic Ions
based on the repulsion of valence pairs of electrons based on the repulsion of valence pairs of electrons
making them as far apart as possible around an making them as far apart as possible around an
atom of a Lewis structure.atom of a Lewis structure.
1) Draw the Lewis structure for the molecule or ion.1) Draw the Lewis structure for the molecule or ion.
2) Determine the number of bonding and unshared pairs attached to 2) Determine the number of bonding and unshared pairs attached to
the central atom.the central atom.
One single, double or triple bond counted as a bonding pairOne single, double or triple bond counted as a bonding pair
3) Choose the appropriate case from the given chart.3) Choose the appropriate case from the given chart.
1-29CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Predict the bond angles of molecules from their Lewis Predict the bond angles of molecules from their Lewis structures. (Review)structures. (Review)
MoleculeMolecule Bonding pairsBonding pairs unshared unshared pairspairs
ShapeShape
HH22OO twotwo twotwo bentbent
NHNH33 threethree oneone Trigonal pyramidTrigonal pyramid
CHCH22OO threethree nonenone Trigonal planarTrigonal planar
CHClCHCl33 fourfour nonenone tetrahedraltetrahedral
CHCH44 fourfour nonenone tetrahedraltetrahedral
CClCCl44 fourfour nonenone tetrahedraltetrahedral
1-30CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Polar and nonpolar moleculesPolar and nonpolar molecules
-
+
Insert elpot ofammonia(page 19)
Insert elpot offormaldehyde(page 20)
H HN
-
+H HC
O
Formaldehyde(polar)
HAmmonia
(polar)
H C C H
Insert elpot ofacetylene(page 20)
Acetylene(nonpolar)
1-31CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Molecular Shape and Polarity Molecular Shape and Polarity (Review)(Review)
MoleculeMolecule Bonding pairs and Bonding pairs and unshared pairsunshared pairs
Electron pair Electron pair distributiondistribution
PolarityPolarity
HH22OO fourfour asymmetricasymmetric polarpolar
NHNH33 fourfour asymmetricasymmetric polarpolar
CHCH22OO threethree asymmetricasymmetric polarpolar
CHClCHCl33 fourfour asymmetricasymmetric polarpolar
CHCH44 fourfour symmetricsymmetric Non-polarNon-polar
CClCCl44 fourfour symmetricsymmetric Non-polarNon-polar
1-32CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Curved arrow Electron pushingCurved arrow Electron pushing
Curved arrowCurved arrow:: a symbol used to show the a symbol used to show the redistribution of valence electronsredistribution of valence electrons
In using curved arrows, there are only two In using curved arrows, there are only two allowed types of electron redistribution:allowed types of electron redistribution:• from a bond to an adjacent atom• from an atom to an adjacent bond
Electron pushing by the use of curved arrows is Electron pushing by the use of curved arrows is also used in explaining reaction mechanismsalso used in explaining reaction mechanisms
1-33CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Drawing Curved ArrowsDrawing Curved ArrowsTo show the movement of electrons in breaking and forming To show the movement of electrons in breaking and forming bonds. The bonds. The tail tail of the arrow is started at the site of electron of the arrow is started at the site of electron density (negative character such as a pi bond or density (negative character such as a pi bond or lone pairlone pair of of electrons) and proceeds to the arrowhead which is drawn to electrons) and proceeds to the arrowhead which is drawn to the site of electron deficiency (positive character). the site of electron deficiency (positive character). NEGATIVE TO POSITIVE!NEGATIVE TO POSITIVE!
Arrows can be drawn from:
1) lone pair
bond
2) bond lone pair
3) bond
bond
tail head
1-34CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
ResonanceResonance
For many molecules and ions with double For many molecules and ions with double bonds, two or more Lewis structure could be bonds, two or more Lewis structure could be writtenwritten
1-35CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Orbital Overlap ModelOrbital Overlap Model
1-36CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Hybrid Atomic OrbitalsHybrid Atomic Orbitals
Hybridization is the mixing up of two or more atomic orbitals
There are three types of hybrid atomic orbitals for There are three types of hybrid atomic orbitals for carboncarbonspsp33 (one s orbital + three p orbitals give four sp3
orbitals)spsp22 (one s orbital + two p orbitals give three sp2
orbitals)spsp (one s orbital + one p orbital give two sp orbitals)
1-37CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Four spFour sp33 hybrids hybrids
Three spThree sp22 hybrids hybrids
Two spTwo sp hybrids hybrids
s and p hybridss and p hybrids
1-38CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
and and bonds bondsOverlap of hybrid orbitals can form two types Overlap of hybrid orbitals can form two types
of bonds, depending on the geometry of the of bonds, depending on the geometry of the overlapoverlap bondsbonds are formed by “direct” overlap
bondsbonds are formed by “parallel” overlap of unhybrid p prbitlas
s1 s1 p1 p1 s1 p1
1-39CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
and and bonds in single and multiple bonds bonds in single and multiple bonds
single bondsingle bond - one shared pair of electrons between - one shared pair of electrons between two atoms; a two atoms; a bond bond
double bonddouble bond - two shared pairs of electrons - two shared pairs of electrons between two atoms; one s bond and one between two atoms; one s bond and one bond bond
triple bondtriple bond - three shared pairs of electrons - three shared pairs of electrons between two atoms; one s bond and two p bondsbetween two atoms; one s bond and two p bonds
1-40CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Bond PropertiesBond Properties
Bond strengthBond strength::
strongeststrongest weakest weakest
Bond lengthBond length::
longest shortestlongest shortest
C C C C C C> >
C CC CC C > >
1-41CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Counting Counting and and bonds in Lewis structure bonds in Lewis structure
H-C-C-HH
H
H
H
H
C C
H
H H
H-C C-H
Hybrid-ization
Types of Bonds to Carbon Example
sp3 four sigma bonds
sp2 three sigma bondsand one pi bond
sp two sigma bondsand two pi bonds
Ethane
Ethylene
Acetylene
Name
1-42CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Predicting hybridization of atoms in a Lewis Predicting hybridization of atoms in a Lewis structurestructure
Count sigma bonds and unshared electrons around Count sigma bonds and unshared electrons around the atomthe atomIf the total number of pairs:
2 sp hybridization
3 sp2 hybridization
4 sp3 hybridization
1-43CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Functional Groups in Organic CompoundsFunctional Groups in Organic Compounds
Functional groupFunctional group:: an atom or group of atoms within a an atom or group of atoms within a molecule that shows a characteristic set of physical and molecule that shows a characteristic set of physical and chemical propertieschemical properties
Functional groupFunctional group• divide organic compounds into classes• the sites of characteristic chemical reactions• the basis for naming organic compounds
1-44CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
AlcoholAlcohol(carbon, hydrogen and (carbon, hydrogen and oxygen)oxygen)
CHCH33-CH-CH
22--OHOH
Thiol Thiol (thioalcohol) thio means (thioalcohol) thio means sulfursulfur
CHCH33-CH-CH
22-SH-SH
AmineAmine CHCH33-CH-CH
22-NH-NH22
EtherEther CHCH33-CH-CH
22-O--O-CHCH22-CH-CH
33
An alcohol (Ethanol)
H-C-C-O-H
HH
HH
CH3 N HH
CH3 N H
CH3
CH3 N CH3
CH3
(a 1° amine) (a 2° amine) (a 3° amine)
Common Functional GroupsCommon Functional Groups
1-45CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Carbonyl group Carbonyl group or unitor unit
AldehydeAldehyde
ketonesketones
Carboxylic acidsCarboxylic acids
O
CH3-C-O-H CH3COOH CH3CO2Hor or
Acetic acid
Common Functional Groups (continued)Common Functional Groups (continued)
1-46CHEM 121, Winter 2009, LA CHEM 121, Winter 2009, LA TECHTECH
Class Functional group Example Classification of organic compoundsClassification of organic compounds