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Unit 9 Notes

Unit 9 Notes. A) Atomic Emission Spectrum – The unique set of lines that each element uniquely makes as electrons return from an excited to a ground state. II.) Electromagnetic Radiation - Energy given off by electrons in the form of light. .

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Unit 9 Notes

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  1. Unit 9 Notes

  2. A) Atomic Emission Spectrum – The unique set of lines that each element uniquely makesas electrons return from an excited to a ground state.

  3. II.) Electromagnetic Radiation - Energy given off by electrons in the form of light.

  4. [As a wave, there are many measurements that can be made] A) Crest - The top of a wave. B) Trough - The bottom of a wave.

  5. C) Amplitude - The distance from the middle to a crest or trough.

  6. D) Wavelength 1) Definition - The length of one wave 2) Symbol - “λ” (lambda) 3) Units – meters (m) 4) Usually very small for EM waves [EM = Electromagnetic]

  7. E) Frequency 1) Definition - Number of waves that pass a point in one second 2) Symbol - “f” 3) Units – Hertz Hz, (1/s), or s-1

  8. F) Speed 1) Speed of light - 3 x 108 m/s 2) All EM radiation travels at the same speed as light 3) Symbol - “c”

  9. G) Equation: c = λ f [ λ f ]

  10. *Label the crest, trough, amplitude, and wavelength of this wave: Crest • Wavelength Amplitude Trough

  11. *What is the frequency of red light which has a wavelength of 700nm ( .0000007 m)? (1m=1000000000nm) (c is in your notes) If c = λ f, then f = c λ f = c = 300000000 m/s λ .0000007 m f = 4.29 x 1014 1/s or Hz

  12. *What is the wavelength of violet light which has a frequency of 7.5 x 1014 Hz ? (Hz = 1/s) If c = λ f, then λ = c f λ = c = 300000000 m/s f 7.5 x 1014 1/s λ = .0000004 m or 400 nm

  13. III.) Photons - When light is like a particle. [Light is like a particle because there are only certain amounts of energy it can have] A) Quantum - The minimum amount of energy light can have.

  14. B) Planck’s Equation – Calculates the amount of energy in light; E = h f 1) E = energy a) Units = J b) J is Joules 2) h = Planck’s Constant = 6.626 x 10-34 Js • 3) f = frequency (Units = Hz = 1/s)

  15. What is the energy of violet light ? E = h f • h = 6.626 x 10-34 Js f = 7.5 x 1014 1/s (from earlier) E = (6.626 x 10-34 Js)(7.5 x 1014 1/s) E = 4.97 x 10-19 J

  16. [Once the minimum amount of energy is calculated, the actual energy can be a multiple of the quantum amount. (1 x E, or 2 x E, or 3 x E, etc)]

  17. Don’t forget how to convert! 8.2 nm = ____ m? 8.2 nm 1 m = .0000000082 m 1000000000 nm = 8.2 x 10-9 m

  18. Title notes – Quantum Mechanical Model of the atom Draw this accurately in landscape orientation • S = 1 orbital = 2 Electrons • P = 3 orbitals = 6 Electrons • D = 5 orbitals = 10 Electrons • F = 7 orbitals = 14 Electrons

  19. Atomic models • Current theory your going to learn about is called quantum mechanical model • Last good theory was Bohr’s Planetary model • Bohr’s model helped explain electron spectra emission

  20. B) Quantum MechanicalModel 1) The new atomic model 2) Difference – Divides energy levels into sublevels with orbitals

  21. D) Energy Sublevels - s, p, d, f 1) The s sublevel only has 1 orbital, and the orbital holds 2 electrons

  22. 2) The p sublevel has 3 orbitals, and each orbital holds 2 electrons for a total of 6

  23. 3) The d sublevel has 5 orbitals, and each orbital holds 2 electrons for a total of 10

  24. 4) The f sublevel has 7 orbitals, and each orbital holds 2 electrons for a total of 14

  25. Electron Configuration Go left to right to show where electrons are in the atom 1s22s2 2p6 3s2 3p6 4s23d10 4p65s2 4d10 5p6 6s2 4f14 5d106p67s2 5f14 6d10 7p6

  26. □ □ □ □ □ 1s 2s 2p hi hi h h h Becomes: 1s2 2s2 2p3

  27. □ □ □□□ □ □□□ □ □□□□□ hi hi hi hi hi hi hi hi hi hi hi hi h h h 1s 2s 2p 3s 3p 4s 3d Becomes: 1s2 2s2 2p6 3s2 3p6 4s2 3d7

  28. Bromine (35 electrons – 35 arrows) □ □ □□□ □ □□□ □ □□□□□ □□□ 1s 2s 2p 3s 3p 4s 3d 4p hi hi hi hi hi hi hi hi hi hi hi hi hi hi hi hi hi h Becomes: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5

  29. 1s2 2s2 2p4

  30. 1s2 2s2 2p63s23p64s23d104p1

  31. The electrons on the s & p sublevels of the highest energy level are called valence electrons. They are the outer most electrons and determine chemical behavior.

  32. IV.) Electron Dot Diagrams (AKA Lewis Dot Diagrams A) Purpose – to identify the valence electrons B) number of dots = which A group it is in. 1) example = 7a = 7 dots (Fluorine) Li Be B C N O F Ne

  33. Things to know from the equations besides the equations • Definition of crest, amplitude, trough, wavelength • Which of the following waves has a higher frequency? Wavelength?

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