Observatims from Ruhunrd atomic mode
Gyoll
foil
33 Only o47 podaca delcd Rboctive
4 Hoadby amy putee detetedby (80) Sourca Collino
Conclusim/ Afomic model
Most of he space M atom is omoty
2 Whsle posithve chat
Change d atmost ctire
mos scomcebat in a snall
This tegioy is called core v.
core o nuens
3 The cone o mcleus is smouwded by
clouds of electos caud eleona
is providud
nuceus amd ekcos
Limitatin of Rrthenard Atomic model
FIH Cadd wot explain veosn bebind line specsm
2 It Could wot erplains reason behind stability of Atom (Cantinugs tevolut
q eluctron )
Continuous Spectrum
-Spiral path
-Nucleus
Emission Line Spectrum
Electron
Distauee of dosest Apbroach’
IH issthe closeost ditauce fron gold nudus ubto which a ponhicde com reoch.
each
a Panti ca gold mu cleus ke þas
kitue Pws Jà Sakta ai
(KE= Pe)
A+ diotomc coget abgroach
estimate
my2
(2e)|ze)
2zez
Impact ponametu>
It is porpendiculaa distance of Veloity vector from Cantral ine
0f nuceus.
S30
Imþact poaa wetu
scatoig
Løsen imbodt þaxa- lae sctoing
b= Kze cte
11
Atomic spea>
When a gas or Sulbsfance is heted then tronsitin elecon occur, &s a
tes wlb, Guengy Teleasdin the fomm o elecro magretie wane
Continuous
contimuos 3e.
Emission
Line
Absorption
(a) Emission Spectra
Emission spectrum
Hot gas Prism
(b) Absorption Specta
Absorption spectrum_
High density Cold gas
hot matter
Bohr's atomic model
Accepting the Rutherford'satomic model of an atom, Bohr proposed an atomic model to explain
spectra emitted by Hydrogen atom. It is based on following Postulates(Assumption)
1) Nuclear Concept- Electrons revolve around nucleus like planets revolve aroånd sun. For this
motion centripetal force is provided by Electrostaticforce of attraction. =to
Quantum Condition) An electron can only revolve in those orbjtsL=nh
whose angular momentuiS
h=663
JL= nh/2|| |myy=1h
201 211
J&,
where nis n= 1,2,3..It is priniciple quantum number and his plank's Constant.
3Mationary Orbits- While revolving in permissible orbits, an electron does not radiate energy.
se non radiating orbits are called stationary orbits.
4) quency Condition-An atom radiates energy only when an electron jumps from one stationary
it of higher energy to another stationary orbit of lower energy.
E= E2 - E1
nel
(n=3) ind sta exitatim Second
(4=2) abit sem excittog
shat fist
(a=1)) sat tunsgy first
first stat Ground
VRadius of Orbit of Hydrogen atom
The necessary centripetal force required by electron is provided by electrostatic Force between
nucleus and electron.
Also we knas taha
mvR=nh Kze
211
myz k.Ze.e
V= nh
2
R
2TT MR
kze
2 nh R= nh
4TmR
4TTmkze
Rn
R an R= nhL
t*mkze
1:4:9 : 16 2s.... 0
R= (scaxio)
4 nx 9-1xt6 9xIz6x.
R = o"S3 A'
Velauty of eehn in Boht odbit
Nesoy Centnp fce to elec io V=217Ke
kze
mv kze V=2TKe
Ch,
2TT kze V
R= kze hh
Alss we kuss thet V- 2Tkze <is callad fne
mVR =nh Mh Structre constant
2|
R = nh
201
Energy of electron revolving-in Bohy bit Totl E= k.E+ PE
Pe = -Kze
KE = 2Lmv Tote Enengy =kétPE E-1 Kze 4rtnkz
E= 1kze kze nh
ke 3 kze 2 R
R E-22etm
E- kze
Radis R, )
R
E.
Also wekuasthat
Pe = kze)(e)
R 41'mkze.
TE=-13 6
PE=-2 (13-6) =27.2W
E,>-13:6 KE, = + 13-6W
Pez
-z(34)=-69w
-3"4 ew -z(1s)=3-00
KEs = tlslew
(2)
-l3"6
32
spectral series of Hydrogen atom
Emited wavelength
Whre n, b loe osbit
Ryd bong cotont, Is value
R= -097X|o l
V[eries obtained due to transitions-.
When electron transits from
"From Any higher state ton=1 Lymanseries ’ Ultrav iolet Reoin
From Any higher state to n=2 Balmer series
visible Ragios
From Any higher state to n=3 Paschen series In fyared.
" From Any higher state to n=4 Bracket series
From Any higher state to n=5 Pfund series Infmrad
MaxiMMm
Bane ’ Maximm
Paschey
Minimym mey Sabhi sanjes ke liye = ea hai
Wavng
H line
ne
line
Miaiw wm
Calculate the Shortest and Longest wavelength of Lyman series.
9I1A
Lomgpotwe
R Su x\o m
Excitation energy
The energy required to transfer an electron from the ground state to an excited state (a state
higher energy) is called the excitation energy of the electron in that state.
(
Excitation Potential
The potential difference through which an electron should be accelerated to reach the
higher energy state from lower energy state is called excitation potential.
fst excitatio E= E2-6
E= -34w-13)
E= -3 t13-G (02
||0-2 V
excitt poti= V=e l·GXIo19
lonisation Potential
" It isthat accelerating that provides sufficient amount of energy to ionize the target atom by
=0
knocking out one of its electrons completely from the atom.
Minimum
Loniseio engy Enig qui red to Gmplete
free cleeron =)Eo -13-6ew
E-f t13-6W
o-3) E:0
