1. Structure of an atom and much more
Submitted By:-
Deepak Saxena of Class ixth
‘B’
Session : 2010-2011
People’s Public School
2. Contents
1. Atom
2. Electrons (e-)
3. Protons (p+)
4. Neutrons (N0
)
5. Modals
5.1 J.J Thomson Modal of ATOM
5.2 Rutherford’s Modal of ATOM
5.3 Bohr’s Modal of ATOM
6. Thanks
4. Atom
“Atoms are said to be the very tiny
particles of any matter that cannot be
divided any more after a certain stage “
for example :
Take a chair and keep on doing its pieces ,
a stage will come when there will small
particle left that particle can be said to
be an atom.
5. Particles in atom
According to today's chemistry I know that
atom has 3 types of particles and they are :
1. Electron
2. Proton
3. Neutron
8. Neutron’s (n0
)
“The that do not have neither positive nor
negative charge on them are named as
Neutron’s .”
9. Comparative table :
Particle Charge on
the
particle
Symbol Location
in atom
Electron -1 unit e-
Outside
the
nucleus
Proton +1 unit p+
In the
nucleus
Neutron No
charge
n0
In the
nucleus
10. Finding of Proton’s, Electron’s
& Neutron’s
There is very simple way to find that an
atom contains how many Protons ,
Electrons , & Neutrons in it .
The only thing that we need to know is
the atomic number of that atom as well
as the mass number of that atom
11. Atomic no. & Mass no.
As we all know that there are 114 known
elements. So to be in an comfortable
manner scientists made up the table
called “ Periodic Table”. This table
consist of all the elements that are
founded till the date.
12.
13. Mass no.
As we make it from the name that I must
be talking about the mass of the atom
taken. The mass is nothing but the sum
of electrons Protons & neutrons . But
actually mass no. can be finded through
just doubling the atomic no. of the given
atom if the atomic no. is even .
If the atomic no. is odd then just double
the atomic no. and add 1 to the answer .
14. Representation of atomic no. and
mass no.
Atomic no. is denoted with ‘X’ , mass no with ‘A’
and atomic no. with say ‘Z’.
Atomic no. is written in downward and mass no.
is written in upward form.
Therefore :
Mass no. = A
X= symbol of element
Atomic no.=z
15. Finding Proton & electron
Now if we know the atomic no. then we
can find both of the proton & electron.
Because the no. of protons and electrons
are directly proportional to the atomic
no. for example :
We take sodium . The atomic no. of
Sodium (Na) is 11 therefore the :-
Atomic no. = no. of Protons = no. of
Electrons
16. Finding of neutrons
There is very easy and simple way to find
neutrons as we had earlier taken sodium
(Na) so the formulae for finding
neutrons is :-
Mass no. – Atomic no. = no. of
neutrons
18. JJ Thomson modal for atom
The first person to suggest a modal for
atom was the sir J.J Thomson .
He assumed that atom is a sphere filled
with the positive charges with the
electrons (e-)
His modal looked like a cake.
19.
20. Saying’s by Thomson
• An atom consist of positive sphere and
electrons in it .
• The negative & positive charges balance
each other .
• Atom as a whole can be said to be
neutral.
21. Rutherford’s Modal of an ATOM
Rutherford made the experiment for the
study of atom.
He made the alpha particles pass through
the atom and observed it.
He found that some of the rays are
reflected. He observed that there are
some particles inside the atom. He
found that he could answer some of the
doubts due to Thomson’s modal
22.
23. Observations by sir Rutherford
• Nucleus of an atom is positively
charged.
• Nucleus of an atom is very dense, hard,
and rigid .
• Nucleus of an atom is very small as
compared to the size of atom (10-9
nm)
as a whole.
24. Bohr proposed that :
1. Electrons revolve around nucleus on
fixed circular paths known as shells .
2. An electron has fixed energy .
3. The shells are called energy levels
represented by K,L,M,N or 1,2,3,4.
Bohr’s modal for ATOM
25.
26. Conclusion
During my project report I have seen
that how was atom defined and have
learnt about its structure .
That the atom has 3 particles inside it , it
has 4 shells that can be written in
K,L,M,N format.
