1. © 2010 Pearson Education, Inc. PowerPoint ® Lectures for College Physics: A Strategic Approach, Second Edition Chapter 29 Atoms and Molecules

2. © 2010 Pearson Education, Inc. Slide 29-2 29 Atoms and Molecules

3. © 2010 Pearson Education, Inc. Slide 29-3

4. © 2010 Pearson Education, Inc. Slide 29-4

5. © 2010 Pearson Education, Inc. Slide 29-5

6. © 2010 Pearson Education, Inc. Spectroscopy Slide 29-10

7. © 2010 Pearson Education, Inc. Continuous Spectra and Blackbody Radiation Slide 29-11

8. © 2010 Pearson Education, Inc. Discrete Spectra of the Elements Slide 29-12

9. © 2010 Pearson Education, Inc. The Hydrogen Spectrum Balmer’s formula Wavelengths of visible lines in the hydrogen spectrum Slide 29-13

10. © 2010 Pearson Education, Inc. Rutherford’s Experiment Slide 29-14

11. © 2010 Pearson Education, Inc. Using the Nuclear Model Ionization The nucleusIsotopes Slide 29-15

12. © 2010 Pearson Education, Inc. Bohr’s Model of Atomic Quantization Slide 29-16

13. © 2010 Pearson Education, Inc. Bohr’s Model of Atomic Quantization (cont’d) Slide 29-17

14. © 2010 Pearson Education, Inc. Frequencies of Photons Emitted in Electron Transitions Slide 29-18

15. © 2010 Pearson Education, Inc. Representing Atomic States Energy-level diagram Slide 29-19

16. © 2010 Pearson Education, Inc. The Bohr Hydrogen Atom Slide 29-20

17. © 2010 Pearson Education, Inc. Energy-Level Diagram of the Hydrogen Atom Slide 29-21

18. © 2010 Pearson Education, Inc. 1.Schrödinger found that the energy of the hydrogen atom is given by the same expression found by Bohr, or The integer n is called the principal quantum number. 2.The angular momentum L of the electron’s orbit must be one of the values The integer l is called the orbital quantum number. The Quantum-Mechanical Hydrogen Atom Slide 29-22

19. © 2010 Pearson Education, Inc. 3.The plane of the electron’s orbit can be tilted, but only at certain discrete angles. Each allowed angle is characterized by a quantum number m, which must be one of the values The integer m is called the magnetic quantum number because it becomes important when the atom is placed in a magnetic field. 4.The electron’s spin can point only up or down. These two orientations are described by the spin quantum number m s, which must be one of the values The Quantum-Mechanical Hydrogen Atom (cont’d) Slide 29-23

20. © 2010 Pearson Education, Inc. Energy and Angular Momentum of the Hydrogen Atom Slide 29-24

21. © 2010 Pearson Education, Inc. Energy Levels in Multielectron Atoms Hydrogen atomMultielectron atom Slide 29-25

22. © 2010 Pearson Education, Inc. Excited States and the Pauli Exclusion Principle Helium atomLithium atom Slide 29-26

23. © 2010 Pearson Education, Inc. The Periodic Table Slide 29-27

24. © 2010 Pearson Education, Inc. Building Up the Periodic Table Slide 29-28

25. © 2010 Pearson Education, Inc. Excitation by Absorption and Collision Slide 29-29

26. © 2010 Pearson Education, Inc. Emission Spectra Slide 29-30

27. © 2010 Pearson Education, Inc. Checking Understanding Suppose that an atomic excited state decays to the ground state by emission of two photons, with energies E 1 and E 2. Is it possible for that excited state to decay to the ground state by emission of a single photon with energy E 1 + E 2 ? A.It is always possible, for every atom. B.It is never possible, for any atom. C.It is always possible for hydrogen atoms, but is unlikely for other atoms. Slide 29-31

28. © 2010 Pearson Education, Inc. Answer Suppose that an atomic excited state decays to the ground state by emission of two photons, with energies E 1 and E 2. Is it possible for that excited state to decay to the ground state by emission of a single photon with energy E 1 + E 2 ? A.It is always possible, for every atom. B.It is never possible, for any atom. C.It is always possible for hydrogen atoms, but is unlikely for other atoms. Slide 29-32

29. © 2010 Pearson Education, Inc. Molecules Slide 29-33

30. © 2010 Pearson Education, Inc. Fluorescence Slide 29-34

31. © 2010 Pearson Education, Inc. Checking Understanding Which of the following is not a possible fluorescence process? A.Absorption of red light and emission of green light B.Absorption of ultraviolet light and emission of infrared light C.Absorption of ultraviolet light and emission of green light D.Absorption of blue light and emission of red light Slide 29-35

32. © 2010 Pearson Education, Inc. Answer Which of the following is not a possible fluorescence process? A.Absorption of red light and emission of green light B.Absorption of ultraviolet light and emission of infrared light C.Absorption of ultraviolet light and emission of green light D.Absorption of blue light and emission of red light Slide 29-36

33. © 2010 Pearson Education, Inc. Stimulated Emission and Lasers Slide 29-37

34. © 2010 Pearson Education, Inc. Photon Amplification Slide 29-38

35. © 2010 Pearson Education, Inc. A Helium-Neon Laser Slide 29-39