This document defines key concepts about matter including: 1) Matter is anything that has mass, occupies space, and can be perceived by the senses. 2) Atoms are the smallest particles of matter that exhibit material properties and usually do not exist independently. Examples are hydrogen and hydrogen atoms. 3) Molecules are formed when atoms combine and have independent existence, such as hydrogen and hydrogen molecules. 4) Homoatomic molecules contain the same type of atoms while heteroatomic molecules contain different types of atoms. Examples are given as hydrogen and water molecules.

1. MATTER

2. 1. Define matter.
2. What is an atom? Give
an example .
3. Define molecule. Give
an example.
4. What are homoatomic
and heteroatomic
molecules?
Give an example of
each.
1. Define matter.
2. What is an atom? Give
an example .
3. Define molecule. Give
an example.
4. What are homoatomic
and heteroatomic
molecules?
Give an example of
each.

3. MATTER
Matter is anything which has
mass, occupies space and can
be perceived by our senses.

4. *
According to JOHN DALTON ,all kinds of matter
are made up of extremely small particles called
atoms.

5. *
ATOM: Atom is the smallest particle of the matter
exhibits all the properties of matter, usually do not have
independent existence .
Example: Hydrogen atom: H
MOLECULE: Atoms combined with each other to form the
molecules having independent existence.
Hydrogen molecule: 𝑯𝟐

6. *
PARTICLES OF MATTER
VERY SMALL
HAVING
INTERMOLECULAR
SPACE
IN CONSTANT
RANDOM MOTION
ATTRACT EACH
OTHER

7. Observation: The solution in all the beakers are coloured though they become
fainter due to successive dilution.
Conclusion: A small crystal of potassium permanganate contains a very large
number of tiny particles which shows all the properties of matter.

8. *
Observation : There is no increase in the level of water in the beaker.
Conclusion :There must be some space between the particles of matter
in which the salt or sugar particles get accommodated when dissolved.

9. BROWNIAN MOTION:
The random motion of the suspended particles on the surface of a liquid or
in air is called brownian motion.
Observation: Pollen grains were moving throughout the water in a zig-zag or
irregular manner.
Conclusion: As water is also made up of tiny particles which are also in
random motion. The pollen grains move in such a way because they collide
with the moving particles of water.

10. Diffusion: The intermixing of two or more
substances due to the motion of their particles in
order to get a uniform mixture is called diffusion
Observation: The reddish Brown vapours also spread out into the upper jar.
Conclusion: The rate of diffusion is the fastest in gases and slowest in
solids. It increases with increase in temperature.

11. *
Question: Why a piece of chalk can be broken easily while a piece of
coal requires a greater force to break and a metal piece cannot be
broken easily?
Answer; Magnitude of force of attraction between the particles called
as intermolecular force of attraction and it varies from matter to
matter. More is the force ,difficult to break it.
Increasing order of intermolecular force of attraction in three type of
matter is :
Chalk < coal < iron

12. STATES OF MATTER :-
SOLIDS
• DEFINITE SHAPE
AND DEFINITE
VOLUME
• EXAMPLE :-
WOOD,STONE ,
ETC .
LIQUIDS
• DEFINITE
VOLUME BUT NO
DEFINITE SHAPE
• EXAMPLE :-
WATER, MILK,
ETC .
GASES
• NEITHER A
DEFINITE SHAPE
NOR A DEFINITE
VOLUME
• EXAMPLE:- AIR,
OXYGEN, ETC .