The main postulates of Bohr's model of the hydrogen atom:-

Electrons in an atom revolve around the nucleus in certain stable orbits without the emission of radiant energy.

The angular momentum of an electron in a stable orbit is quantized and is an integral multiple of h2π2πh​, where hh is Planck's constant.

mvr=nh/2π

where:

• m is the mass of the electron,
• vv is the velocity of the electron,
• r is the radius of the orbit,
• n is an integer (1, 2, 3, ...)

Electrons can only absorb or emit energy in discrete quanta when they move from one orbit to another. The energy absorbed or emitted (ΔE) is given by:

ΔE=hν

where ν is the frequency of the emitted or absorbed radiation.

Electrons in stable orbits do not radiate energy, and these orbits are called stationary orbits.

This is in contrast to classical physics, where an accelerated charge (such as an electron in orbit) should radiate energy according to classical electromagnetic theory.

The centripetal force required to keep the electron in its circular orbit is provided by the electrostatic attraction between the electron and the nucleus.

It can be expressed as :-

(1/4πϵ₀) e²/r²=mv²/r

where:

• ϵ0​ is the permittivity of free space,
• e is the charge of the electron.