1. Lecture 2110/24/05

2. Light Emission vs. Absorption Black body

3. Dual Nature of Light Wave Refraction Diffraction Particle Photoelectric effect

4. Line Emission Spectrum “Excited” atoms emit light

5. Line Emission Spectrum

6. Balmer series Rydberg equation Balmer Series

7. Atomic Spectra and Bohr 1. 1.Any orbit should be possible and so is any energy. 2.But a charged particle moving in an electric field should emit energy. Electron would eventually run out of energy

8. Bohr New theory : Quantum or Wave Mechanics e- can only exist in certain discrete orbits Stationary states e- is restricted to QUANTIZED energy states.

10. n= principal quantum number n is an integer n with the lowest possible energy is said to be in the ground state Electrons with higher energy than ground state are said to be in an excited state

11. Calculate the energies of n=1, n=2, and n=3 states of the hydrogen atom in J/atom. R = 1.097 x 10 7 m -1 h = 6.626 x 10 -34 J-s c = 2.998 x 10 8 m/s