It's PPT on Thomson model of atom for class 9. everything included in ppt is in textbook of science class 9.It is very easy to understand. Hope it help's you!

1. NAME : GAURI .V.
SARDAL
CLASS : 9 Y
ROLL NO. : 36

2. TOPIC :
- BY GAURI S

3. Dalton’s atomic theory suggested that atom was
indivisible (which could not be broken down into
smaller particles) .
But the discovery of sub-atomic particles such as
electrons & protons inside the atom disproved this
postulate of Dalton’s atomic theory.
The discovery of electrons and protons suggested
that atoms are divisible.

4. Now the big question was :
How these electrons &
protons were arranged
inside the atom?
[Please note that the third subatomic
particle (neutron) had not been discovered
at that time ]

5. For explaining this, many
scientists proposed various
atomic models.
J.J. Thomson was the first
one to propose a model for
the structure of an atom.

6. JOSEPH JHON THOMSON
J.J. Thomson (1856-
1940), was born on
18 December 1856. He
was awarded the Nobel
prize in Physics in 1906
for his work on the
discovery of electrons.
He directed the Cavendish
Laboratory at Cambridge for
35 years and seven of his
research assistants
subsequently won
Nobel prizes.

7. J.J. THOMSON , IN 1904 PROPOSED
THAT :
1) An atom consists of a uniform sphere (or ball)
of positive charges (due to presence of proton)
with negatively charged electrons embedded in it
.
2) The negative and positive charges are equal in
magnitude, due to which an atom is electrically
neutral. It has no overall positive or negative
charge.

8. The colored area in sphere
contains all positive charges
in the atoms .
The negatively charged
electrons are spread
throughout the positive
charge.
The total negative charge of electron
is equal to the total positive charge
of the sphere.
This equal and opposite charges balance each other
due to which an atom becomes electrically neutral on
the whole.

9. J.J.Thomson’s Model of Atom Watermelon
Negatively
charged
(electron)
Spherical
cloud of
positively
charge
(proton)
This model is been compared with a water melon in
which seeds are embedded or with a pudding
containing dry fruits.

10. • It failed to explain how the positive
charge holds on the electrons inside
the atom.
• It failed to explain how protons and
electrons were arranged in atom so
close to each other.
Although Thomson’s model of atom
explained the electrically neutral
nature of atom.

11. • It also failed to explain an
atom's stability.
• It was unable to explain
the scattering
experiment of
Rutherford.
So, it was rejected