Chapter 1-ContinueChapter 1-ContinueIntroduction to Organic Chemistry
Writing Dot Lewis Structure with Writing Dot Lewis Structure with multiple center atomsmultiple center atomsCarbons 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 Total Valence electron:
H = 4 x1 = 4C = 2 x 4 = 8O = 2 x 6 = 12Total = 24
SkeletalC is less electro negative than OO does not bond to O
H C
H
H
C
O
O H
Bonding
C C O
O
H
H
H
H
Total e- = 24
bonding e - = 14
e- lef t = 10
C C O
O
H
H
H
H
Complete Octet
NOT :)) must form multiple bond
C C O
O
H
H
H
H
Total = 24 e-Bonding = 16Nonbonding = 8e- lef t = 0
Correct
ExampleExampleWrite a Dot Lewis Structure for
CH3NH2
VSEPR TheoryVSEPR TheoryVSEPR 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 ThoeryVSEPR ThoeryCommon shape and angles
◦Linear (180o)◦Tetrahedral (109.5o)◦Trigonal planar (120o)
See table 1.2 page 5
ExamplesExamplesComplete the following Dot Lewis
structure by adding the missing lone-pair then predict the bond angles
a.
b.
c.
C C
H
H Cl
H
H C
O
H
C NC
H
H
H
9
Elements in Organic CompoundsElements 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
10
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.
Functional GroupsFunctional Groups
AlcoholAlcoholAn alcohol
contains the hydroxyl (-OH) functional group.R-OH
R C
R
R
O H
Functional group
R = H or Carbon group (alkyl)
H3C C
H
H
O H
H3C C
CH3
H
O H
H3C C
CH3
CH3
O H
1o alcohol
2o alcohol
3o alcohol
Types of Alcohol
Writing structural formulas of Writing structural formulas of AlcoholAlcohol
CH4OMolecular formula
CH3OHCondensed formula
C
H
OH
H
H
Structural formualMethanol
Writing structural Formulas of Writing structural Formulas of AlcoholsAlcoholsDraw 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
AminesAmines
In amines, the functional group is a nitrogen atom. RNH2, R2NH or R3H |
—N —
H3C N
H
H Methylamine
1o amine
H3C N
CH3
H
H3C N
CH3
CH3
Dimethylamine
2o amine
Trimethylamine
3o amine
ExamplesExamplesDraw structural formulas of the
three secondary amines with the molecular formula C4H11N
Carboxylic AcidsCarboxylic Acids
Carboxylic acids contain the carboxyl group, which is a carbonyl group attached to a hydroxyl group. –COOH
O ║
— C—OH
ExamplesExamplesDraw condensed structural
formulas for the two carboxylic acids with molecular formula C4H8O2
Carboxylic estersCarboxylic estersAn ester contains the carboxyl group between carbon atoms.
–COOR or –CO2R
C
O
O C
Functional group
ExamplesExamplesDraw structural formulas for the
four esters with the molecular formula C4H8O2
20
Learning CheckLearning CheckClassify 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 O ║ ║
4) CH3─C─OH 5) CH3─C─O─CH3
ExamplesExamplesConsider 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
