Question

what are postulates of bhor's model of atom

Answer 1

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) (E2 > 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.

Answer 2

Answer:

1) An electron can revolve around the nucleus in certain fixed orbits of definite energy without emission of any radiant energy. Such orbits are called stationary orbits.

2) An electron can make a transition from a stationary state of higher energy E2 to a state of lower energy E1 and in doing so, it emits a single photon of frequency,ν=E2−E1/h where h is the Planck's constant.

Conversely, on absorbing an energy, E2−E1 when the electron is at energy E1, the electron can make a transition from E1 to E2.

3) Only those orbits are allowed for which the angular momentum of the electron is an integral multiple of h2π,Thus, L=nh2π where n=0,1,2,....