In Bohr's atomic model, electrons revolve around the nucleus in specific, quantised orbital with fixed energy levels.
Here's a more detailed breakdown of the postulates:
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Electrons revolve in specific orbits:
Electrons in an atom only revolve around the nucleus in certain circular orbits, also known as energy shells or energy levels.
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Orbits have fixed energy:
Each orbit or shell has a fixed energy, and these circular orbits are also known as energy levels.
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No energy radiation in orbits:
As long as an electron remains in an orbit, it neither absorbs nor emits energy, meaning the atom remains stable.
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Energy transitions:
Energy is absorbed or emitted only when electrons transit from one energy level to another.
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Quantized angular momentum:
Electrons can only revolve in those orbits for which the angular momentum (mvr) of the electron is an integral multiple of h/2π, where h is Planck's constant.
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Orbit designations:
The circular orbits are numbered as 1, 2, 3, 4, or designated as K, L, M, and N shells, with the K shell (n=1) being the closest to the nucleus and associated with the lowest energy.
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Energy absorption and emission:
When an electron absorbs energy, it jumps from a lower energy level to a higher energy level, and when it returns from a higher energy level to a lower energy level, it emits energy.