Organic Structure• Among neutral (uncharged) organic compounds

– carbon: carbon: four covalent bonds and no unshared pairs of electrons– hydrogen:hydrogen: one covalent bond and no unshared pairs of electrons– nitrogen:nitrogen: three covalent bonds and one unshared pair of electrons– oxygen:oxygen: two covalent bonds and two unshared pairs of electrons– a halogen:a halogen: one covalent bond and three unshared pairs of electrons

Models• Draw a lewis structure, make the model, draw ther 3-D

structure, and decribe the bond angles for the following:• C2H6

• C2H4

• C2H2

• C2H5Cl• C2H4O• CH2O• CH5N

Alcohols

• Alcohol:Alcohol: contains an OH (hydroxyl) group bonded to a tetrahedral carbon atom

– may be primary (1°), secondary (2°), or tertiary (3°)

CH3-C-OH

H

HCH3-C-OH

CH3

HCH3-C-OH

CH3

CH3

A 1° alcohol A 3° alcoholA 2° alcohol

R-C-O-HR

RCH3CH2OH

H

HH

HH-C-C-O-H

Structuralformula

Functional group(R = H or carbon

goup

Condensedstructuralformula

::

Alcohols

• Problem:Problem: Draw Lewis structures, make the model, and describe the geometry and polarity for the two alcohols of molecular formula C3H8O

Alcohols

• Problem:Problem: draw Lewis structures and condensed structural formulas for the two alcohols of molecular formula C3H8O

• Solution:Solution:

CH3CH2CH2OH

CH3CHCH3

OH

H-C-C-C-O-HH

H

H

H

H

H

C-C-C-HH

H

O

HH

H

H

H

A primary alcohol

A secondary alcohol

Lewis stucturesCondensed structural

formulas

::

::

Amines

• Amine:Amine: a compound containing an amino amino groupgroup– the amino group may be primary (1°), secondary

(2°), or tertiary (3°)

CH3NH

CH3

CH3NH2 CH3NCH3

CH3

(CH3)3N(CH3)2NH

Methylamine(a 1° amine)

Dimethylamine(a 2° amine)

Trimethylamine(a 3° amine)

or or

Amines

– Problem:Problem: Draw Lewis structures, make the model, and describe the geometry and polarity for the two primary amines of molecular formula C3H9N

Amines

– Problem:Problem: draw condensed structural formulas for the two primary amines of molecular formula C3H9N

– Solution:Solution:

CH3CH2CH2NH2C-C-C-NH2 C-C-C

NH2

CH3CHCH3

NH2

The three carbons may be bonded to nitrogen

in two ways

Add seven hydrogens to give eachcarbon four bonds and give the

correct molecular formula

Aldehydes and Ketones• Both contain a C=O (carbonyl) groupC=O (carbonyl) group

– aldehyde:aldehyde: contains a carbonyl group bonded to a hydrogen; in formaldehyde, the simplest aldehyde, the carbonyl group is bonded to two hydrogens

– ketone:ketone: contains a carbonyl group bonded to two carbon atoms

CH3CHO O

CH3CCH3C-C-HR

R

ROC-C-C

O

RR

RR

R R

Functionalgroup

Functionalgroup

Acetaldehyde(an aldehyde)

Acetone(a ketone)

Aldehydes and Ketones

– Problem:Problem: Draw Lewis structures, make the model, and describe the geometry and polarity for the two aldehydes of molecular formula C4H8O

Aldehydes and Ketones

– Problem:Problem: draw condensed structural formulas for the two aldehydes of molecular formula C4H8O

• Solution:Solution:

CH3CH2CH2CH

OCH3CHCH

O

CH3

CH3CH2CH2CHO CH3CHCHO

CH3

or or

Carboxylic Acids

• Carboxylic acid:Carboxylic acid: a compound a compound containingcontaining a -COOH (carboxyl: carbcarbonyl + hydroxyloxyl) group • in a condensed structural formula, a

carboxyl group may also be written -CO2H.

RCOHO

CH3COHO

Functionalgroup

Acetic acid(a carboxylic acid)

Carboxylic Acids

– Problem:Problem: Draw Lewis structures, make the model, and describe the geometry and polarity for the single carboxylic acid of molecular formula C3H6O2

Carboxylic Acids

– Problem:Problem: draw a condensed structural formula for the single carboxylic acid of molecular formula C3H6O2

• Solution:Solution: the only way the carbon atoms can be written is three in a chain; the -COOH group must be on an end carbon of the chain

CH3CH2COOHCH3CH2COH

Oor