Question

describe Bohr's atomic model and describe it's usefulness
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Answer 1

Bohr model of the atom was proposed by Neil Bohr in 1915. ... Bohr modified this atomic structure model by explaining that electrons move in fixed orbitals (shells) and not anywhere in between and he also explained that each orbit (shell) has a fixed energy level.

Bohr's atomic model explained the stability of an atom. According to Bohr, an electron revolving in a particular orbit cannot lose energy. Therefore, emission of radiation is not possible as long as the electron remains in one of its energy levels and hence there is no cause of insatbility in his model.