All organic compounds consist of carbon atom.Properties of carbon atom:-has 4 valence electrons.-can form 4 covalent bonds.

Single bondDouble bondTriple bond

Structural formula shows how the atoms in a molecule are bonded to each other.3 types of structural formula:condensed structureexpanded structureskeletal structure

2- Dimensional formula Condensed StructureDoes not show single bonds between carbon and hydrogen atoms, but double and triple bonds are shown.All atoms that are attached to a carbon are written immediately after that carbon. C4H9Cl CH3CHClCH2CH3 (Condensed structure)

C4H8CH3CH=CHCH3 (Condensed structure)

Examples:ii) Cyclohexane, C6H12iii) Aldehyde, CH3CHO

Expanded StructureExpanded structures indicate how atoms are attached to each other but are not representations of the actual shapes of the molecules.

C4H9ClMolecular Formula Expanded structure

Examples:i) Alcohol (C2H6O)

ii) Carboxylic acid (C3H6O2 )

Skeletal StructureShows only the CARBON SKELETON.Hydrogen atoms are not written. Other atoms such as O, Cl, N etc. are shown.Bonds are represented by lines i) CH3CH(Cl)CH2CH3 = Cl

ii) =

QuestionCondensed StructureExpanded StructureSkeletal Structure

CH3(CH2)CCl(CH3)2

3- Dimensional formula ( wedge dashed wedge line formula )Describes how the atoms of a molecule are arranged in space.

Example : Bromomethane

or or Indication :- :bonds that lie in the plane :bonds that lie behind the plane :bonds that project out of the plane

A carbon atom can be classified asprimary carbon (1o) bonded to 1 C secondary carbon (2o) bonded to 2 Ctertiary carbon (3o) bonded to 3 Cquarternary carbon (4o) bonded to 4 CClassification of C atoms:

Example:

1. The classification of carbon atoms*

Exercise:

How many 2 C atoms 3o C atoms 4o C atoms 1o H atomsare present ? Answer:

3 atoms3 atoms1 atom15 atoms

Example:

3. The classification of alcohol4. The classification of haloalkanes5. The classification of amines*

11.3FUNCTIONAL GROUPS AND HOMOLOGOUS SERIES Functional group is an atom or a group of atoms that determines the chemical properties of a organic compound.

Why functional groups are important?

Functional groups are important for three reasons: They are the units by which we divide organic compounds into classes.

They are sites of chemical reaction; a particular functional group, in whatever compound it is found, undergoes the same types of chemical reactions.

Functional groups serve as a basic for naming organic compounds.*

Homologous are compounds belonging to the same homologous series

A homologous series is a functional group of compounds of similar structures and properties with the same functional group.

*

Some important functional groups in organic compounds :- *

Homologous SeriesFunctional groupGeneral FormulaExampleAlkanenoneCnH2n+2CH4 MethaneAlkeneC = C (double bond)CnH2nCH2 = CH2 EtheneAlkyneC C (triple bond)CnH2n-2CH CH EthyneArene

(aromatic ring)CnH2n-6

Methylbenzene

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AlcoholOH (hydroxyl)CnH2n+1 OHCH3CH2OH Ethanol EtherOR (alkoxy)CnH2n+2OCH3OCH3 MethoxymethaneHaloalkaneX (halogen)CnH2n+1X CH3CH2ClChloroethaneAldehyde

(carbonyl)CnH2nOCH3C=O H EthanalKetone

(carbonyl)CnH2nOCH3C=O CH3 Propanone

Carboxylic acid

(carboxyl)CnH2nO2Alkanoic acidCH3C=O OH Ethanoic acidAcyl halide

(acyl)CnH2n+1COClAlkanoyl chlorideCH3C=O Cl Ethanoyl chlorideEster

(ester)CnH2nO2Alkyl alkanoateCH3COOCH3 Ethyl ethanoateAmide

(amide)CnH2n+1 CONH2- amideCH3CONH2EthanamideAmine-NH2 (amino)CnH2n+1 NH2- amineCH3NH2Methanamine

Exercise 1:*

Exercise 2:*

Exercise 3:

Determine the functional groups of each structuresR O R`R NAlkoxy AminoCarboxylHydroxylCarbonyl R OH R = O

Exercise 4:

Describe the functional groups in the following structures 1.4.3.2.Acyl chloride

Exercise 5: Label the functional groups in the following structures

Exercise 6: Classify the following compounds into their respective families*