Summary Nomenclature Simplified: Easy to Understand Notes

Classification and
01 Nomenclature

Vital Force Theory (VFT) : By Berzelius in 1815
Upto 1815, any organic compound could not be synthesized in laboratory. So Berzelius suggested that
there is a mysterious force in living organisms which was named as Vital Force and said that organic
compounds cannot be synthesized in laboratory. This theory was called as vital force theory (VFT). But
in 1828 a German scientist Wohler synthesized an organic compound in laboratory which was 'urea',
so VFT was failed. Urea was synthesized in lab by heating of ammonium cyanate (NH4CNO).
NHCNO  NH2—C—NH2
4
Rearrangement
Ammonium cyanate O
Urea
Organic Compounds
Hydrocarbons and their derivatives are called as organic compounds.
Tetravalency of Carbon
Atomic number of carbon atom is 6 and it has four valence electrons so C-atom is tetravalent.

2S 2p

In ground state (here covalency of carbon is 2)
First excited state (here covalency of carbon is 4)



Available for bond formation

Representation of Organic Compound
(i) Molecular Formula:
C2H6, C2H6O
(ii) Structural Formula:
HH H H
C2H6 H—C—C—H , C2H5OH H—C—C—O—H
H H HH
(iii) Condensed Structural Formula:
CH3CH2CH2CH2CH3 → CH3(CH2)3CH3
CH3
CH3—CH2—C—CH2—CH3→ CH3CH2C(CH3)2CH2CH3 or (CH3CH2)2C(CH3)2

CH3

, Organic Chemistry
(iv) Bond-Line Formula:
In this system C-H bond and C–C bond are represented by lines.
CH2
(1) CH3  CH3 
(2) CH —C
3 C—CH 3 
Cl Cl
(3) CH
CH 
CH3
CCH
CH2
(4) CH3 CH2 

Hybridisation
Structure  and  Hybridisation Bond angle Shape
bonds
4, 0 sp3 109°28' Tetrahedral
—C—

3, 1 sp2 120° Planar (Trigonal)
—C=
—C 2, 2 sp 180° Linear

=C= 2, 2 sp 180° Linear


Type of Carbon and Hydrogen
(i) 1° or Primary Carbon/1° Hydrogen :- Carbon atom attached to no other carbon or to only one
carbon is called primary carbon. Hydrogen atom attached with 1° or primary carbon.
(ii) 2° or Secondary Carbon/2° Hydrogen :- Carbon atom directly attached to two carbon atoms is
known as 2° or secondary carbon. Hydrogen atom attached with 2° or secondary carbon.
(iii) 3° or Tertiary Carbon/3° Hydrogen :- Carbon atom directly attached to three other carbon atoms
is known as 3° or tertiary carbon. Hydrogen atom attached with 3° or tertiary carbon.
(iv) 4° or Quaternary Carbon :- Carbon atom directly attached with four other carbon is known as 4°
or quaternary carbon.

S.No. Functional Group (Common name)
1. R—X Alkyl halide
2. R—OH Alkyl alcohol
3. R—NH2 Alkyl amine
4. R—CN Alkyl cyanide
5. R—NC Alkyl isocyanide
6. R—O—R Dialkyl ether
7. R—NH—R Dialkyl amine
8. R—N—R Trialkyl amine
R
9. R—C—R Dialkyl ketone
O

, Classification and Nomenclature
Classification of Organic Compounds
Organic Compound



Open chain or acyclic
compound



Saturated Unsaturated


Alkane
CH3–CH2–CH3 Alkene Alkyne
Propane CH3–CH=CH2 HCCH
Propene Ethyne


Closed chain or
Cyclic compound




Homocyclic Heterocyclic
compound compound



O N
Cyclohexane Benzene Tetrahydrofuran Pyridine

Homologous Series
A group or class of organic compounds which containing same functional group with increasing molecular
weight, constitutes a homologous series.

(a) The various members are called homologue.


(b) Two successive homologues differ by CH2 group or 14 molecular weight.


(c) All the homologues can be prepared by similar methods.


(d) Homologues have similar chemical properties but there is a regular change in physical
properties like melting point, boiling point etc.


(e) All the members can be represented by same general formula.