Bohr’s Atomic Model Applications, Limitations, Important Points, JEE 2025
Shrivastav 5 Jun, 2024
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Bohr’s Atomic Model Applications : Hey there, fellow science enthusiasts! Have you ever wondered how tiny atoms make up everything around us? Well, Niels Bohr's atomic model is like a treasure map that helps us navigate the mysterious world of atoms. In this article, we'll delve into the practical applications of Bohr's atomic model and also explore its limitations. Get ready for an exciting journey through the atomic realm.
Before we dive into the applications and limitations, let's quickly recap Bohr's atomic model. Imagine the atom as a tiny solar system, with a nucleus at the center and electrons orbiting around it in fixed energy levels or "shells." Bohr proposed that these electrons can only occupy certain energy levels, and they jump between these levels by absorbing or emitting energy in the form of light.
Bohr's model explains the discrete spectral lines observed in atomic spectra, such as the line spectrum of hydrogen. It also provides insights into the stability of atoms and helps us understand how atoms interact with light and other forms of energy. Now, let's explore some real-world applications of Bohr's atomic model.
Applications Of Bohr’s Atomic Model
1. Radius of Various Orbits (Shell)
Coulombic force =
Where, K = 9 × 10 9 Nm 2 /coulomb 2
As we know – Coulombic force = Centrifugal force
Also,
Putting the value of v from eqn. (2) to eqn. (1)
…(3)
Putting the value of
h, m, K, & e (Constants) in the above eqn. (3)
{1Å = 10
–10
m = 10
–8
cm}
This formula is only applicable for hydrogen and hydrogen like species i.e., species containing single electron.
2. Velocity of an electron
Since coulombic force = Centrifugal force
Putting the value of Angular momentum
k, e & h
3. Time period (T)
Time taken for complete revolution in n
th
orbit =
4. Frequency of Revolution (v n ):
Number of revolutions per unit time in n
th
orbit =
Limitations of the Bohr’s Model
1. Bohr’s theory does not explain the spectrum of multi electron atom.
2.
Why the Angular momentum of the revolving electron is equal to
3. Bohr interrelate quantum theory of radiation and classical law of physics with out any theoretical explanation. This was the biggest drawback of this model.
4. Bohr’s theory does not explain the fine structure of the spectral lines. Fine structure of the spectral line is obtained when spectrum is viewed by spectroscope of more resolution power.
5. Bohr theory does not explain the spiliting of spectral lines in the presence of magnetic field (Zemman’s effect) or electric field (Stark’s effect).
Important Points To Remember
Bohr’s atomic model in applicable only for monoelectronic species like H, He + , Li +2 , Na 10+ , U 91+ etc.
Solved Example Of Bohr’s Atomic Model Applications
1. Calculate the radius of 1 st , 2 nd , 3 rd , 4 th Bohr’s orbit of hydrogen
Sol.:
Radius of Bohr’s orbit:
(a) Radius of 1
st
orbit:
(b) Radius of 2
nd
orbit:
(c) Radius of 3
rd
orbit:
(d) Radius of 4
th
orbit:
2. How much time an e – will take for one complete revolution in 2 nd orbit of He + ;
Sol.:
Time taken =
3. Calculate the de Broglie wavelength of a ball of mass 0.1 kg moving with a speed of 30 ms –1 .
Sol.:
This is apparent that this wavelength is too small for ordinary observation.
Although the de Broglie equation is applicable to all material objects but it has significance only in case of microscopic particles.
Since, we come across macroscopic objects in our everyday life, de Broglie relationship has no significance in everyday life.
4.
The energy level of an atom for 1
st
, 2
nd
and 3
rd
levels are E, 4E, 2E respectively. If photon of wavelength
Sol.:
Bohr’s Atomic Model Applications FAQs
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