1. Chapter 5 “Electrons in Atoms” Pre-AP Chemistry Charles Page High School Stephen L. Cotton

8. The Bohr Model of the Atom Niels Bohr I pictured the electrons orbiting the nucleus much like planets orbiting the sun. However, electrons are found in specific circular paths around the nucleus, and can jump from one level to another .

11. Schrodinger’s Wave Equation Equation for the probability of a single electron being found along a single axis (x-axis) Erwin Schrodinger Erwin Schrodinger

16. Principal Quantum Number Generally symbolized by “n”, it denotes the shell (energy level) in which the electron is located. Maximum number of electrons that can fit in an energy level is: 2n 2 How many e - in level 2? 3?

17. Summary s p d f # of shapes (orbitals) Maximum electrons Starts at energy level 1 2 1 3 6 2 5 10 3 7 14 4

23. aufbau diagram - page 133 Aufbau is German for “building up” Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f

25. Pauli Exclusion Principle No two electrons in an atom can have the same four quantum numbers. Wolfgang Pauli To show the different direction of spin, a pair in the same orbital is written as:

38. Irregular configurations of Cr and Cu Chromium steals a 4s electron to make its 3d sublevel HALF FULL Copper steals a 4s electron to FILL its 3d sublevel

44. - Page 139 “ R O Y G B I V” Frequency Increases Wavelength Longer

45. Parts of a wave Origin Wavelength Amplitude Crest Trough

46. Electromagnetic radiation propagates through space as a wave moving at the speed of light. Equation: c =  c = speed of light, a constant (2.998 x 10 8 m/s)  (nu) = frequency, in units of hertz (hz or sec -1 )  (lambda) = wavelength, in meters

48. - Page 140 Use Equation: c = 

49. Radiowaves Microwaves Infrared . Ultra-violet X-Rays GammaRays Long Wavelength Short Wavelength Visible Light Low Energy High Energy Low Frequency High Frequency

50. Wavelength Table Long Wavelength = Low Frequency = Low ENERGY Short Wavelength = High Frequency = High ENERGY

56. The energy ( E ) of electromagnetic radiation is directly proportional to the frequency (  ) of the radiation. Equation: E = h  E = Energy, in units of Joules (kg·m 2 /s 2 ) (Joule is the metric unit of energy) h = Planck’s constant (6.626 x 10 -34 J·s)  = frequency, in units of hertz (hz, sec -1 )

63. Experiment #6, page 49-

65. { { {

68. Wave-Particle Duality J.J. Thomson won the Nobel prize for describing the electron as a particle . His son, George Thomson won the Nobel prize for describing the wave-like nature of the electron. The electron is a particle! The electron is an energy wave!

69. Confused? You’ve Got Company! “ No familiar conceptions can be woven around the electron; something unknown is doing we don’t know what .” Physicist Sir Arthur Eddington The Nature of the Physical World 1934

72. Heisenberg Uncertainty Principle You can find out where the electron is, but not where it is going. OR… You can find out where the electron is going, but not where it is! “ One cannot simultaneously determine both the position and momentum of an electron.” Werner Heisenberg

74. Moving Electron Photon Before Electron velocity changes Photon wavelength changes After Fig. 5.16, p. 145

75. End of Chapter 5