CarbonTetravalency Tetravalency

Carbon forms 4 covalent bonds as it Carbon forms 4 covalent bonds as it has four valence electrons. It could has four valence electrons. It could gain four electrons to form C4- gain four electrons to form C4- anion or lose four electrons to form anion or lose four electrons to form C4+ cation. Both these conditions C4+ cation. Both these conditions would take carbon far away from would take carbon far away from achieving stability by the octet rule. achieving stability by the octet rule. To overcome this problem carbon To overcome this problem carbon undergoes bonding by sharing its undergoes bonding by sharing its valence electrons. This allows it to valence electrons. This allows it to be covalently bonded to one, two, be covalently bonded to one, two, three or four carbon atoms or atoms three or four carbon atoms or atoms of other elements or groups of of other elements or groups of atoms.atoms.

CatenationCatenation

The ability of an element to The ability of an element to

catenate is primarily based on catenate is primarily based on the the

bond energy of the element to bond energy of the element to

itself.  itself. 

Carbon has the ability to form Carbon has the ability to form both both

sigma and pi bonds to itself. sigma and pi bonds to itself. This This

Is due to an overlap between Is due to an overlap between pi-pi-

electron orbitals, allowing electron orbitals, allowing electron electron

density to be shared and thus density to be shared and thus

stabilizing the bond. stabilizing the bond. 

11 CARBONCARBON

ORGANIC COMPOUND STRUCTURAL RPESENTATIONORGANIC COMPOUND STRUCTURAL RPESENTATION

Carbon22 Organic Compounds :: Structural RepresentationOrganic Compounds :: Structural Representation

Here in the Lewis dot structure of carbon we can see the tetra-valency of the carbon .

In general in Lewis dot structure the valency electrons are shown

Other ExamplesOther Examples

33 Lewis StructureLewis Structure

44 Deriving Lewis Dot StructuresDeriving Lewis Dot Structures

Rule :-1Rule :-1Rule :-1Rule :-1

Rule :-2Rule :-2Rule :-2Rule :-2

Rule :-3Rule :-3Rule :-3Rule :-3

Rule :-4Rule :-4Rule :-4Rule :-4

Find the total number of Valence Electrons (T.V.E’s)Find the total number of Valence Electrons (T.V.E’s)Find the total number of Valence Electrons (T.V.E’s)Find the total number of Valence Electrons (T.V.E’s)

To identify the central atomTo identify the central atomTo identify the central atomTo identify the central atom

Complete the octet for the outer atomsComplete the octet for the outer atomsComplete the octet for the outer atomsComplete the octet for the outer atoms

Find the formal charge (F )Find the formal charge (F )Find the formal charge (F )Find the formal charge (F )

F = T.V.E – no. of bonds around the atom – no. of lone F = T.V.E – no. of bonds around the atom – no. of lone electrons electrons

In this structural formula Carbon and hydrogen In this structural formula Carbon and hydrogen atoms are not indicated and carbon chains are atoms are not indicated and carbon chains are

indicated by zigzag lines. The line junctions indicate indicated by zigzag lines. The line junctions indicate CHCH22 group and the line terminals indicate CH group and the line terminals indicate CH33 group group

55 BondBond lineline structurestructure

OCTANE CHLOROCYCLOHEXANE PENTYL

CYCLOPROPANE 1,1,2,2-TETRAMETHYLETHANE CYCLOPENTANE

66 Condensed structureCondensed structure

the bonds in the plane of the paper are shown in their normal bond convention i.e., with a straight line

the bonds away from the observer are showed by dashed wedges

the bonds away from the observer are showed by dashed wedges

77 3-D Representation Of Organic 3-D Representation Of Organic MoleculesMolecules

Primary(1°) – attached to ONE other carbon

Secondary(2°) – attached to TWO other carbons

Tertiary(3°) – attached to THREE other carbons

Quaternary(4°) –attached to FOUR othercarbons

88 Types of CarbonsTypes of Carbons

Organic Compounds

Homocyclic or Carbocyclic compounds

Aromatic compounds

Acyclic or open chain compounds

Heterocyclic compounds

Benzenoid compounds

Cyclic or Closed chain or Ring compounds

Alicyclic compounds

Non-benzenoid compounds

99 Classification Of Organic Compounds

Functional Group An Atom or Group of atoms joined in a specific manner which are responsible for the characteristic chemical properties of the organic compounds

Homologous seriesA group or a series of organic compounds eachcontaining a characteristic functional groupforms a homologous series .The successive members differ from each other in molecular formula by a –CH2 unit.

1010 Functional Group And Homologous Functional Group And Homologous seriesseries

IUPAC NAMINGIUPAC NAMINGInternational Union of Pure And Applied ChemistryInternational Union of Pure And Applied Chemistry

The names of these compounds are based on the number of carbons in the longest i.e., parent chain like the word root ‘Meth’ for 1 and so on and these end with suffix ‘-ane’

1111 IUPAC Nomenclature of AlkanesIUPAC Nomenclature of Alkanes

Number of Carbons

Wood Root

IUPAC Name

Structure

1 Meth Methane CH4

2 Eth Ethane C2H6

3 Prop Propane C3H8

4 But Butane C4H10

5 Pent Pentane C5H12

6 Hex Hexane C6H14

7 Hept Heptane C7H16

8 Oct Octane C8H18

9 Non Nonane C8H20

10 dec Decane C10H22

1212 Rules For the IUPAC Naming of Branched Chain HydrocarbonsRules For the IUPAC Naming of Branched Chain Hydrocarbons

Rule :-1

Rule :-2

Rule :-3

Rule :-4Rule :-4

Rule :-5

Rule :-6

Rule :-7

To Identify the longest carbon chain containg largest To Identify the longest carbon chain containg largest number of carbon number of carbon atomsatoms

To number the carbon chain from that end which in near to To number the carbon chain from that end which in near to the alkyl groupthe alkyl group

Numbers and letters are separated by small dash.Numbers and letters are separated by small dash.

To give the name to the parent chain containing the given To give the name to the parent chain containing the given number of carbon number of carbon atomsatomsIdentify the alkyl group and to write their names as prefix Identify the alkyl group and to write their names as prefix to that parent to that parent alkyl along with proper positionalkyl along with proper positionIf different alkyl group are present their names are written If different alkyl group are present their names are written alphabetically alphabetically along with position as prefixalong with position as prefix

If two or more alkyl group are present then prefixes di, tri If two or more alkyl group are present then prefixes di, tri etc are used to etc are used to indicate the numbers and their positions.indicate the numbers and their positions.

1313 Functional Groups and Hydrocarbons :- The GroupsFunctional Groups and Hydrocarbons :- The Groups

S. No Class of Compound

Functional Group

Prefix Suffix Example

1 Alkane - -ane Methane

2 Alkene - -ene Ethene

3 Alkyl - -yne Butyl

4 Haloalkane Cl Chloro Halo

- Chloromethane

Br Bromo Bromomethane

5 Alcohol Hydroxyl Hydroxyl -ol methanol

6 Aldehyde Formyl -al propanal

7 Ketone Keto -one propanone

8 Carboxylic Acid Carboxy -oic acid Butanoic acid

9 Esters Carbonyl -oate butanoate

10 Ethers Alkoxy

11 Amines Amino Amine

12 Amides carbomoyle -amide

13 Acid Chlorine Halo Carboxyl -olyhalide

14 Nitrocompound

15 Cynides Cyano Nitrite

Chapter 2 17

1414 .... And Their Structures.... And Their Structures

Carboxylic Acid

1515 Some Specific Rules Related To Functional GroupsSome Specific Rules Related To Functional Groups

Aldehyde

Numbering should be Started From the Carbon Which Contains the Aldehyde Group

General RuleGeneral Rule

If the letter next to the ‘e’ of alkane is a vowel then ‘e’ is cancelled and if the next letter to ‘e’ of alkane is consonant then ‘e’ is retained

1166

IUPAC Nomenclature of poly functional group and the order of priorityIUPAC Nomenclature of poly functional group and the order of priority

If the compounds contains two or more diff If the compounds contains two or more diff functional groups then in these compounds one functional groups then in these compounds one functional group is considered as the principal functional group is considered as the principal functional group and written as suffix and the functional group and written as suffix and the remaining functional groups are considered as remaining functional groups are considered as secondary functional groups and written as secondary functional groups and written as prefixes . The priority order is :-prefixes . The priority order is :-

Carboxylic acid Carboxylic acid >> Ester Ester >> Acid Acid chloride chloride >> amide amide >> Cyano Cyano >> aldehyde aldehyde >> Keto Keto >> Hydroxy Hydroxy >> amine amine >> double Bond double Bond >> triple triple bond bond >> halogen halogen

1177

ExamplesExamples