Bohr's atomic theory:
In 1913 neil bohr, proposed a model for an atom that was consistent with Rutherford model. But it also explains the abserved line spectrum of the hydrogen atom.
Main postulates of bohr atomic theory:
- The electron in an atom revolves around the nucleus in one of the circular orbit. Each orbit has a fixed energy. So each orbit is also called energy level.
- The energy of the electron in an orbit is proportional to its distance from the nucleus. The further the electron is from the nucleus,the more energy it has.
- The electron revolves only in those orbits for which angular momentum of the electron in an integral multiple of h/2×3.14
h:
H is planks constant its value is 6.626×10 power -10 j.s. - Light is obsorbed when an electron jumps to a higher energy orbit and emitted when electron jumps to a lower energy orbit. Electron present in a particular orbit does not radiate enrgy.
- The energy of the light emitted is exactly equal to the difference between the energies of the orbit.