Neil Bohr Model of Atom
Bohr Discovery
Neil Bohr presented a model of atomic structure in 1913, known as Bohr’s atomic model, which depicted an atom as a tiny, positively charged nucleus surrounded by electrons that move in circular orbits around the positively charged nucleus like planets do around the sun in our solar system.
Findings of Bohr theory
- Without emitting radiant energy, electrons move in stable orbits around the nucleus. Each orbit contains a certain amount of energy and is known as an energy level or shell.
- K, L, M, and N shells are used to describe an orbit or energy level. The term “ground state” refers to the electrons lowest energy level.
- When an electron changes its orbit or energy level, it either emits or absorbs energy. It produces energy when it jumps from a higher to a lower energy level, and it absorbs energy when it goes from a lower to a higher energy level.
- According to Plank’s equation, the energy received or released is equal to the difference between the energies of the two energy levels (E1, E2).
ΔE = E2-E1 = h𝜈
ΔE = energy received or released
h= Plank’s constant
𝜈= frequency of radiation
- The angular momentum of an electron revolving in different orbits is given by:
mvr = nh/2π
Where,
n= number of energy shell; 1, 2, 3 …..
me= mass of an electron
v= velocity
r=radius
h= Plank’s constant
Limitations of Bohr model
- The Heisenberg Uncertainty Principle is violated. Heisenberg states that it is impossible for an object to have both a known location and momentum at the same time
- When bigger atoms are taken into account, the Bohr atomic model theory contains inaccurate spectrum predictions. This is true for smaller atoms like hydrogen.
- It was unable to explain the Zeeman phenomenon, which occurs when a magnetic field causes the spectral line to break into many components.
- It was unable to explain the Stark effect, which occurs when an electric field causes the spectral line to break into smaller lines.
Continue Reading -> Defects of Bohr model in detail
Conclusion:
According to the Bohr model, an atom consists of a tiny, positively charged nucleus that is around by orbiting electrons. Bohr was the first to determine that electrons move in different orbits around the nucleus and that an element’s properties are determined by the number of electrons in its outer orbit.
Continue Reading -> Rutherford Atomic Model (Gold Foil Experiment)
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