The Bohr model is a relatively primitive model of the hydrogen atom, compared to the valence shell atom. Postulates of Bohr's Model of an atom are- an Atom consists of a small, heavy, positively charged nucleus in the centre and the electrons revolve around it in circular paths known as orbits these discrete orbits have fixed radii and energy and are called as energy levels or shells, these are numbered as 1, 2, 3 etc or k, l, m, n and so on as we move outward from the nucleus. While revolving i