1. Wave Nature of Matter

2. De Broglie Wavelength

3. Wave-particle duality apply also to matter.

4. Early Models of Atoms

5. Thomson’s Model

6. Rutherford’s Model

8. Atomic Spectra

10. The Rutherford model, as it stood, was unable to explain why atoms emit line spectra.

11. The Bohr Model

12. Bohr’s First Postulate
The angular momentum of electron is quantized.

13. Allowed Angular Momenta

14. Allowed Radii

16. Bohr’s Second Postulate
An electron doesn’t radiate when it is in one of the allowed orbits (stationary state).

17. Energy Levels of Atom

18. Bohr’s Third Postulate
A single photon is emitted whenever an electron jumps down from one orbit to another.

20. De Broglie’s Hypothesis Applied to Atoms