1.
Prof. Sohaib Hasnain
Punjab Group of Colleges, Faisalabad
CHEMISTRY

2.
WHAT IS MOLECULE

3.
A molecule is the smallest particle of a pure
substance which can exist independently.

4.
WHAT IS PURE SUBSTANCE ?
Element
Atomic Elements
Na, Li, Ca, K, Fe
 Molecular Elements
O2, Cl2, O3
 Compound
Molecular Compound
H2SO4, CO2, C6H12O6, C6H6, CH4
Ionic Compounds
NaCl, NaBr, KCl, NaF

5.
“Molecular Elements and
Molecular Compounds are
termed as Molecule because
these exist independently”

6.
MOLECULAR ELEMENT
 Oxygen
MOLECULAR COMPOUND
 Methane

7.
Why Molecule Exists Independently?
 Molecule is formed by the combination of atoms
Atom forms bond to get stability
Molecule is stable specie because it is formed by the combination of
atoms
Molecule exist independently, because it is formed by the unstable
atoms which are now stable

8.
CLASSIFICATION OF MOLECULES
On the basis of following parameter:
 ATOMICITY
 NATURE
 SIZE

9.
ATOMICITY
The number of atoms present is a molecule is called atomicity
Examples
SUBSTANCE MOLECULE ATOMICITY
Carbon Dioxide CO2 3
Sucrose C12H22O11 45
Methane CH4 5
Sulphuric Acid H2SO4 7
Water H2O 3
Ethyl Alcohol C2H5OH 9

10.
TYPES OF MOLECULE ON THE BASIS OF
ATOMICITY
 Mono-atomic Molecule
The molecule which contain only atom.
Examples : Noble Gases ( He, Ne, Ar, Kr, Xe and Rn)
 Poly-atomic Molecule
The molecule which contain two or more, same or different kinds of atoms
Examples : CO, CO2, H2SO4, C12H22O11, C2H5OH, H2O, CH4

11.
TYPES OF MOLECULE ON THE BASIS
OF NATURE
 Homo-atomic Molecule
The molecule which are made up of same or one kind of atoms.
Examples : He, Cl2, O3, P4, S8
 Hetero-atomic Molecule
The molecule which are made up of different kinds of atoms
Examples : HCl, NH3, H2SO4,C6H12O6
.

12.
TYPES OF MOLECULE ON THE BASIS
OF SIZE
Micro-molecules
 They are small in size
 They are simple molecule
 They exist as monomer
Examples
CO2, H2O, CH4
Macro-molecules
 They are large in size
 They have large no. of atoms
 They are exist as polymer
Examples
Haemoglobin, Starch, Cellulose
Chlorophyll

13.
HAEMOGLOBIN

14.
What is Haemoglobin
 It is a blood protein
 It carries oxygen from lungs and transport to the all parts of body
 Each molecule of hemoglobin is made up of 10000 atoms
 It is made up of Carbon, Hydrogen, Nitrogen, Oxygen and Iron
 It is 68000 times heavier than the hydrogen atom

15.
STRUCTURE OF HEMOGLOBIN