#### CHAPTER 12 ATOMS

Bohr’s atomic model

1. An electron in an atom could revolve in certain stable orbits without the emission of radiant energy.

2. The angular momentum of electron is an integer multiple of (h/2π)

where n = 1, 2. 3,… called principle quantum number or orbit number.

3. The radiation of energy occurs only when any electron jumps from one permitted orbit to another permitted orbit. Energy of emitted photon will be,

$=-{\mathrm{R}}_{\mathrm{H}}\left(\frac{1}{{{\mathrm{n}}_{2}}^{2}}-\frac{1}{{{\mathrm{n}}_{1}}^{2}}\right)$

where E1 and E2 are energies of electron in orbits.