1. Excited State vs. Ground State

2. e-e- e-e- Ground state Excited state Electrons can only be at specific energy levels, NOT between levels.

3. Color = Energy of Photons Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 329

4. Energy Level Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 329 A B CD Ground state Energy Four excited states

5. An Excited Lithium Atom Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 326 Photon of red light emitted Li atom in lower energy state Excited Li atom Energy

6. An Excited Lithium Atom Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 326 Photon of red light emitted Li atom in lower energy state Excited Li atom Energy

7. Excitation of Hydrogen Atoms Zumdahl, Zumdahl, DeCoste, World of Chemistry  2002, page 328

8. Return to Ground State

9. Frequency A Frequency B Frequency C n = 2 n = 1 n = 3

10. Frequency A Frequency B Frequency C n = 2 n = 1 n = 3 A B C A + B = C