REVISION NOTES
STRUCTURE OF ATOM
subatomicSymbol Charge Mass Discoverer Experiment
Electron 2 -
1 . 6 X10 9C 9 /x10 .
kg Thomson Cathode
Ray
Proton 1.6X10- 19C 1.6 X 1827 Rutherford Anode
P +
199
6x1027 Chadwick
Ray
Neutron 1 X-Bombard-
H O
kg
.
-ment of
Thomson Model of ATOM : Beryllium
·
electron are uniformly distributed .
·
atom is neutral
·
net the charge =
net-ye charge
·
Also known as water melon model or
plum pudding model.
&
RUTHERFORD MODEL OF ATOM :
-
source of
-particle
lead plate X
photographic
-
>
plate
-
-
-
Y
-
>
-
-
>
*
·
Most X-particles went straight .
very few deflected
·
·
1 i 2000 bounce back.
↳ Most of space is empty
.
↳ Most of the mass and positive
charge is concentrated in small region
called nucleus
revolving
-
Nucleus is surrounded by electrons in circular path
called as oub it.
, DRAWBACK OF RUTHERFORD MODEL
⑧
·
charged particles when accelerated emit energy
in form of electromagnetic radiation
·
Revolving electron would lose energy and finally
fall into nucleus
· failed to explain stability of atom .
Atomic Number (2) = no of protons
Mass number (A) =
no of protons + no of neutrons
A
A-2 = no of element
Z
ISOTOPES ISOBARS ISOTONES
same atomic number
same mass number same no.
but different atomic mass. but different atomic number of neutrons but
eg Protium Deuterium Tritium 40 different atomic
, , e .
g YAU soca number
! 4 in 34
-
e
gN's
ELECTROMAGNETIC RADIATION :
According to maxwell , energy is emitted
continuously from source in the form of radiations travelling in
any
form and associated with electric field and
wave magnetic field oscillating
perpendicular to each other and to the direction of radiation .
·
They travel in vaccum .
· Do notrequire any medium for
propagation
CHARACTERISTICS OF WAVES
·
Wavelength (x) : Distance blu two consecutive crest and trough
1 %= 10-m ,
Lnm = 10-3m , 20m =
10-12 m
Frequency (v) No
·
·
of waves passing through a point in one second.
Unit =
Heutz or Sect
·
Velocity (vorc :
in
Distance travelled by waves one second .
velocity of light (c) = 3x108m/s
·
Wave Number (r) :
Number of wave per unit length unit = m
- =
1
STRUCTURE OF ATOM
subatomicSymbol Charge Mass Discoverer Experiment
Electron 2 -
1 . 6 X10 9C 9 /x10 .
kg Thomson Cathode
Ray
Proton 1.6X10- 19C 1.6 X 1827 Rutherford Anode
P +
199
6x1027 Chadwick
Ray
Neutron 1 X-Bombard-
H O
kg
.
-ment of
Thomson Model of ATOM : Beryllium
·
electron are uniformly distributed .
·
atom is neutral
·
net the charge =
net-ye charge
·
Also known as water melon model or
plum pudding model.
&
RUTHERFORD MODEL OF ATOM :
-
source of
-particle
lead plate X
photographic
-
>
plate
-
-
-
Y
-
>
-
-
>
*
·
Most X-particles went straight .
very few deflected
·
·
1 i 2000 bounce back.
↳ Most of space is empty
.
↳ Most of the mass and positive
charge is concentrated in small region
called nucleus
revolving
-
Nucleus is surrounded by electrons in circular path
called as oub it.
, DRAWBACK OF RUTHERFORD MODEL
⑧
·
charged particles when accelerated emit energy
in form of electromagnetic radiation
·
Revolving electron would lose energy and finally
fall into nucleus
· failed to explain stability of atom .
Atomic Number (2) = no of protons
Mass number (A) =
no of protons + no of neutrons
A
A-2 = no of element
Z
ISOTOPES ISOBARS ISOTONES
same atomic number
same mass number same no.
but different atomic mass. but different atomic number of neutrons but
eg Protium Deuterium Tritium 40 different atomic
, , e .
g YAU soca number
! 4 in 34
-
e
gN's
ELECTROMAGNETIC RADIATION :
According to maxwell , energy is emitted
continuously from source in the form of radiations travelling in
any
form and associated with electric field and
wave magnetic field oscillating
perpendicular to each other and to the direction of radiation .
·
They travel in vaccum .
· Do notrequire any medium for
propagation
CHARACTERISTICS OF WAVES
·
Wavelength (x) : Distance blu two consecutive crest and trough
1 %= 10-m ,
Lnm = 10-3m , 20m =
10-12 m
Frequency (v) No
·
·
of waves passing through a point in one second.
Unit =
Heutz or Sect
·
Velocity (vorc :
in
Distance travelled by waves one second .
velocity of light (c) = 3x108m/s
·
Wave Number (r) :
Number of wave per unit length unit = m
- =
1
