Bohr's Postulates

What is a Bohr postulate?

First let's clarify that it is a postulate; It is said that a postulate is a principle that is admitted as true without the need to be demonstrated and that serves as a basis for other reasoning.

So Bohr's postulates are accepted principles and are used as demonstrations because it was agreed, even if they are not verified.

In 1913, Niels Bohr developed his famous atomic model according to three fundamental postulates:

Bohr's three postulates

Bohr's first postulate:

Electrons describe circular orbits around the nucleus of the atom without radiating energy. The reason why the electron does not radiate energy in its orbit is, for the moment, a postulate, since according to classical electrodynamics a charge with an accelerated movement must emit energy in the form of radiation. That is why it is a postulate, since it contradicts some things that are known for sure.

Bohr's Second Postulate:

The electron does not radiate energy while it remains in an orbital, and emits it when it passes from a higher state of energy to a lower one; this energy variation is equal to the amount of radiation emitted.

Third Bohr postulate:

The atom can emit or absorb a photon of electromagnetic radiation by transitioning the electron from one orbit to another, so that the total energy is conserved. When the electron passes from an orbit of higher to lower energy, it emits a photon.

The difference between the second and third postulates is simple, the second basically says that an electron does not radiate energy if it remains in its orbit, while the second says that it emits or absorbs energy when jumping out of orbit.