Bohr’s Postulates or Bohr’s Model of the Hydrogen Atom!1. An atom has a number of stable orbits in which an electron can reside without the emission of radiant energy. Each orbit corresponds, to a certain energy level.2. An electron may jump spontaneously from one orbit (energy level E1) to the other orbit (energy level E2) (E> E1); then the energy change AE in the electron jump is given by Planck’s equation∆E = E2-E1 = hvWhere h = Planck’s constant.And v = frequency of light emitted.3. The motion of an electron in a circular orbit is restricted in such a manner that its angular momentum is an integral multiple of h/2π, Thusmvr = nh/2π, where m = mass of the electronv = velocity of the electronr = radius of the orbit ann = an integer called principal quantum number of the electron.4. A special surface around nucleus which contained orbits of equal energy and radius was called shell. These shells are numbered from inside to outwards as 1, 2, 3, 4 etc. and called K, L, M, N etc., respectively.
3 4 3