What is the association between electrons and their stationary orbits?

Hint :The Bohr model of the atom is an atomic model proposed by Neil Bohr in 1915. It came as a modification of Rutherford’s model of an atom which said the atom has a nucleus (positively charged) surrounded by negatively charged electrons. Bohr modified this atomic model by explaining that electrons move in fixed orbitals and not anywhere in between.

Complete Step By Step Answer:
According to the first Bohr Postulate, in an atom, electrons which are negatively charged will revolve around the positively charged nucleus in a definite circular path called orbits or shells. The orbit will have fixed energy and these are circular in nature.
The letter ‘n’ is used to represent each of the stationary orbits.
Electrons will occupy the shells 1, 2, 3, 4, 5….
If one of the electrons is in n=1 orbit and the other one is in n=2 orbit we can safely say that the energy of an electron in n=2 orbit will have more energy than that in orbit n=1.
The electrons in an atom can move from a lower energy level to a higher energy level by gaining the required energy through processes such as photon absorption. An electron moves from a higher energy level to lower energy level by losing energy which is emitted as radiation and this will give us the emission spectra of the molecule.

Note :
When we say the electron orbits the nucleus it is not in the manner of a planet orbiting the sun, but instead they exist as standing waves. The electrons are never in a single point location, we can find electrons throughout the volume of the atom. The probability of finding an electron at a single point can be found from the wave function of the electron.