1. Electrons in Atoms Chapter 5

2. Section 5.1 Light and Quantized Energy

3. The Nature of Light Understanding the nature of light was important to understanding the structure and behavior of atoms Understanding the nature of light was important to understanding the structure and behavior of atoms LIGHT= ELECTROMAGNETIC RADIATION LIGHT= ELECTROMAGNETIC RADIATION Electromagnetic radiation: energy that acts as a wave as it travels through space Electromagnetic radiation: energy that acts as a wave as it travels through space

4. Electromagnetic Spectrum Includes all forms of electromagnetic radiation Includes all forms of electromagnetic radiation Some forms of radiation we can not see Some forms of radiation we can not see

5. Radio waves Micro- waves Infrared. Ultrav iolet X-Rays Gamma Rays Low energy High energy Low Frequency High Frequency Long Wavelength Short Wavelength Visible Light

6. 6 Just how long is a wavelength? This diagram gives perspective to just how long a wavelength is by representing some object that is approximately the same size below the spectrum. Note that this diagram is set up opposite to the one on the last slide. Long wavelength on the left side this time.

7. Parts of Waves Wavelength is the distance from crest to crest of a wave Wavelength is the distance from crest to crest of a wave - Represented by Greek letter: λ Frequency is the number of waves that pass one point in a second Frequency is the number of waves that pass one point in a second - Represented by Greek letter: ν Amplitude is the height of the wave Amplitude is the height of the wave

8. Wave

9. Frequency

10. Speed of Light All waves in the electromagnetic spectrum have the SAME SPEED All waves in the electromagnetic spectrum have the SAME SPEED Speed Limit of the Universe: Speed Limit of the Universe: 3.00 x 10 8 m/s There is a mathematical relationship between the WAVELENGTH and FREQUENCY of a wave There is a mathematical relationship between the WAVELENGTH and FREQUENCY of a wave C= λ ν C= λ ν C= speed of light C= speed of light λ = wavelength λ = wavelength ν = frequency ν = frequency

11. Practice Problem After careful analysis, an electromagnetic wave is found to have a frequency of 7.8 x10 6 Hz. What is the wavelength of the wave? After careful analysis, an electromagnetic wave is found to have a frequency of 7.8 x10 6 Hz. What is the wavelength of the wave?

12. ANSWER ANSWER: 3.85 x 10 1 m = 38.5m ANSWER: 3.85 x 10 1 m = 38.5m

13. Practice Problem # 2 What is the frequency of light with a wavelength of 4.90 x 10 -7 m? What is the frequency of light with a wavelength of 4.90 x 10 -7 m?

14. ANSWER 6.12 X 10 14 Hertz 6.12 X 10 14 Hertz

15. Photon A beam of light: A beam of light: has properties of waves and particles has properties of waves and particles is really a bundle of energy made of photon particles that moves as a wave is really a bundle of energy made of photon particles that moves as a wave

16. Photons Planck- ENERGY IS QUANTIZED Planck- ENERGY IS QUANTIZED - Comes in CHUNKS - Quantum- minimum amount of energy that can be gained or lost by an atom - Energy comes in multiples of 6.62 x 10 -34 J-s (PLANCK’S CONSTANT) - Equation: E = hv - E is the energy (JOULES) - v = frequency (Hertz)

17. PRACTICE Calculate the energy of a photon that has a frequency of 9.5 x 10 13 Hz. Calculate the energy of a photon that has a frequency of 9.5 x 10 13 Hz. Calculate the energy of a photon that has a wavelength of 4.5 x 10 -7 m. (NOTE: For this problem you will need to use TWO equations… c = λ ν AND E = hv Calculate the energy of a photon that has a wavelength of 4.5 x 10 -7 m. (NOTE: For this problem you will need to use TWO equations… c = λ ν AND E = hv

18. Answers… 1. 6.29 x 10 -20 J 2. 4.42 x 10 -17 J

19. Atomic Emission Spectra You can EXCITE electrons in atoms by giving them energy You can EXCITE electrons in atoms by giving them energy When excited electrons release energy, they release (or EMIT) LIGHT When excited electrons release energy, they release (or EMIT) LIGHT Electrons of different elements release different amounts of energy Electrons of different elements release different amounts of energy Different amounts of energy = emit different colors of light Different amounts of energy = emit different colors of light

20. Atomic Spectra Atomic Spectrum- set of frequencies (colors) emitted by atoms of an element Atomic Spectrum- set of frequencies (colors) emitted by atoms of an element What colors have the highest frequencies? What colors have the highest frequencies? What colors have the highest energies? What colors have the highest energies?

21. - Each element has its own unique spectra…the lines indicate what frequencies are emitted by the element

22. Section 5.2 Quantum Theory and the Atom

23. Bohr’s Model of the Atom Hydrogen has one proton and one electron Hydrogen has one proton and one electron The electron can ONLY orbit the nucleus at CERTAIN distances (quantized levels) The electron can ONLY orbit the nucleus at CERTAIN distances (quantized levels) When the electron is CLOSEST to the nucleus, it has the LOWEST energy When the electron is CLOSEST to the nucleus, it has the LOWEST energy The lowest energy state is the ground state The lowest energy state is the ground state Any state above the ground state is called excited state Any state above the ground state is called excited state

24. Energy level Examples

25. Quantum number (n) Bohr assigned a number to each orbit called the QUANTUM NUMBER (n) Bohr assigned a number to each orbit called the QUANTUM NUMBER (n) Electrons in the closest orbit to the nucleus have the LOWEST energy (n = 1) Electrons in the closest orbit to the nucleus have the LOWEST energy (n = 1)

26. When elements emit light… Electrons release energy, drop to an orbit that is closer to nucleus Electrons release energy, drop to an orbit that is closer to nucleus Can only “jump” down certain amounts, only release certain amounts of energy Can only “jump” down certain amounts, only release certain amounts of energy These energies correspond to different colors These energies correspond to different colors Different elements produce different colors Different elements produce different colors

27. de Broglie equation All moving particles have wave characteristics All moving particles have wave characteristics Electrons orbit the nucleus with wave motion Electrons orbit the nucleus with wave motion Anything that moves makes waves – can’t see this with large objects Anything that moves makes waves – can’t see this with large objects λ=h/mv λ=h/mv m=mass m=mass

28. Heisenberg Uncertainty Principle Picture the blades of a fan moving quickly around in a circle. It is impossible to distinguish where exactly a single blade of the fan is at any point because the blades are moving too fast. Electrons are also moving too fast for us to distinguish EXACTLY where they are in the atom Electrons are also moving too fast for us to distinguish EXACTLY where they are in the atom Heisenberg uncertainty principle: it is impossible to know precisely both the speed and position of a particle at the same time Heisenberg uncertainty principle: it is impossible to know precisely both the speed and position of a particle at the same time  Area where e- probably is = electron cloud

29. We now call electron clouds…Atomic Orbitals Most probable place to find an electron Most probable place to find an electron An area that surrounds the nucleus An area that surrounds the nucleus Different shapes of orbitals exist Different shapes of orbitals exist

30. Principal Quantum Number (n) (n) indicates how far away the orbital is from the nucleus (n) indicates how far away the orbital is from the nucleus (n) gives the ENERGY LEVEL of the e- (n) gives the ENERGY LEVEL of the e- When (n) gets bigger the distance between the e- and the nucleus increases When (n) gets bigger the distance between the e- and the nucleus increases As n increases, energy level increases As n increases, energy level increases

31. Energy Sublevels Each principal energy level contains sublevels Each principal energy level contains sublevels n = 1 (first energy level) has ONE SUBLEVEL n = 1 (first energy level) has ONE SUBLEVEL n = 2 (second energy level) has TWO sublevels n = 2 (second energy level) has TWO sublevels n = 3 has THREE sublevels n = 3 has THREE sublevels n = 4 has FOUR sublevels n = 4 has FOUR sublevels e- exist in sublevels e- exist in sublevels

32. TYPES OF SUBLEVELS: s Orbitals Spherical Spherical Each s orbital can hold 2 electrons Each s orbital can hold 2 electrons Nucleus is in the center Nucleus is in the center

33. P orbitals Look like Dumb-bells Look like Dumb-bells 3 different p orbitals: each go in a different direction 3 different p orbitals: each go in a different direction Each can hold 2 electrons Each can hold 2 electrons 6 e- can go here, 2 in each orbital  P orbitals together, nucleus is in center ↓

34. P Orbitals

35. D orbitals 5 different shapes 5 different shapes Each type can hold 2 electrons Each type can hold 2 electrons 2 dumb-bells together 2 dumb-bells together

36. F orbitals Have seven different shapes Have seven different shapes 2 electrons per shape 2 electrons per shape

37. F orbitals http://www.youtube.com/watch?v=K-jNgq16jEY

38. Energy Levels If there are electrons in higher energy levels (5, 6, 7) there are STILL FOUR sublevels If there are electrons in higher energy levels (5, 6, 7) there are STILL FOUR sublevels EACH ORBITAL IN A SUBLEVEL HOLDS 2 e-!!!!!!! EACH ORBITAL IN A SUBLEVEL HOLDS 2 e-!!!!!!!

39. Energy Levels… ENERGY LEVEL ONE ENERGY LEVEL ONE ONE SUBLEVEL = S orbital ONE SUBLEVEL = S orbital ONE S orbital (sphere) ONE S orbital (sphere) Each orbital holds TWO electrons Each orbital holds TWO electrons 2 electrons MAX in 1 st Energy Level 2 electrons MAX in 1 st Energy Level ENERGY LEVEL TWO ENERGY LEVEL TWO TWO SUBLEVELS = S, P TWO SUBLEVELS = S, P ONE S orbital (sphere) ONE S orbital (sphere) THREE P orbitals (three dumb-bells) THREE P orbitals (three dumb-bells) 8 Electrons MAX in 2 nd Energy Level 8 Electrons MAX in 2 nd Energy Level P orbitals in 2 nd Energy level fit on TOP of s orbital in second energy level… http://www.youtube.com/watch?v=VfBcfYR1VQo

40. Energy Levels… ENERGY LEVEL THREE ENERGY LEVEL THREE THREE SUBLEVELS = S, P, D THREE SUBLEVELS = S, P, D ONE S orbital  2 e- ONE S orbital  2 e- THREE P orbitals  6 e- THREE P orbitals  6 e- FIVE D orbitals (5 different shapes)  10 e- FIVE D orbitals (5 different shapes)  10 e- 18 e- MAX in THIRD LEVEL 18 e- MAX in THIRD LEVEL ENERGY LEVEL 4, 5, 6, 7 ENERGY LEVEL 4, 5, 6, 7 - FOUR SUBLEVELS = S, P, D, F THREE SUBLEVELS = S, P, D THREE SUBLEVELS = S, P, D ONE S orbital  2 e- ONE S orbital  2 e- THREE P orbitals  6 e- THREE P orbitals  6 e- FIVE D orbitals  10 e- FIVE D orbitals  10 e- SEVEN F orbitals (7 shapes)  14 e- SEVEN F orbitals (7 shapes)  14 e- 32 e- MAX 32 e- MAX HOW MANY TOTAL e- CAN BE IN LEVEL 6? HOW MANY TOTAL e- CAN BE IN LEVEL 6? http://www.youtube.com/watch?v=sMt5Dcex0kg&feature=related

41. Energy Level Sublevels Types of Orbitals Total # e- in sublevel Total # e- in Energy Level 1s122 2s12 p368 3s12 p36 d51018 4s12 p36 d510 f71432

42. Summary s p d f # of shapesMax electronsStarts at energy level 121 362 5103 7144

43. Section 5.3 Electron Configurations

44. Electron Spins… Each orbital can hold TWO electrons Each electron in the orbital MUST have opposite spins One electron spins clockwise, the other spins counter clockwise Represented by an ↑ and a ↓

45. Electron Configuration for an element… Electron Configuration: distribution of electrons in an atom among energy levels and sublevels FORMAT: 1s 2 Energy Level  ↑ Orbital  Number of e- in sublevel Orbital Diagram: ↑ Energy Level 1: one sublevel (s) Up arrow and down arrow = e- w/ opposite spins  Each box represents ONE orbital that can hold TWO electrons…

46. The Electron Configuration of an Atom is governed by THREE rules RULE ONE: AUFBAU PRINCIPLE Electrons occupy orbitals with LOWEST energy FIRST Which orbitals have the lowest energy?? The orbitals that are CLOSEST to the nucleus SOMEWHAT of a pattern is followed… Need TO MEMORIZE (orbitals from lowest : 1s  2s  2p  3s  3p  4s  3d  4p  5s  4d  5p  6s  4f  5d  6p  7s  5f  6d  7p  6f  7d  7f

47. Remember… Each s orbital can hold a maximum of TWO electrons There are THREE types of p orbitals, and each orbital can hold 2 e-, so 6 e- can go in the p-orbitals There are FIVE types of d orbitals, and each orbital holds 2 e-, so 10 e- can go in the d- orbitals There are SEVEN types of f orbitals, and each orbital holds 2 e-, so 14 e- can go in the f orbitals # e- s2 p6 d10 f14

48. Electron Configurations… Electrons in atoms exist in LOWEST ENERGY LEVELS FIRST (closest to nucleus) GO to higher energy levels if lower levels are filled EX: - - Helium has 2 protons and 2 electrons - - 2 electrons are in n = 1 energy level - - 1 st Energy level has one type of orbital: s - - S can hold 2 e- - - ELECTRON CONFIGURATION (i.e. where electrons are for helium) = 1s 2  Up and Down arrows = opposite spins

49. Electron Configurations… Lithium has atomic number three… Li has THREE protons and THREE electrons What is Li’s e- configuration?? Electron occupy CLOSEST orbitals first (s sublevel of first energy levels) Only TWO electrons can occupy 1s sublevel THIRD electron must go in NEXT highest energy level (2 ND Energy level) The s-orbital of the 2 nd Energy Level is the next closest orbital CONFIGURATION: 1s 2 2s 1

50. Electron Configurations… Be has an atomic number of 4 (4 protons, 4 electrons) Electron Configuration: 1s 2 2s 2 Now try B… (atomic number 5) Remember… the second energy level has TWO sublevels (s and p) First two electrons in the second energy level go in the 2s orbital. Where do the rest go? Electron configuration:

51. Now try Neon Neon has an atomic number 10 How many total e- does Ne have? What is Ne’s electron configuration?

52. The easy way to remember 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f  Make this table: -Highest energy level on top w/ sublevels in order (left to right) s, p, d, f -2 e- per orbital -Draw a diagonal line starting from bottom -Write e- configuration: 1s 2

53. Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 4 electrons

54. Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 12 electrons

55. Fill from the bottom up following the arrows 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 6f 7s 7p 7d 7f 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 38 electrons

56. PRACTICE Write the electron configurations for… C S Si F Na Al Br Ar Mn Sr

57. Increasing energy 1s 2s 3s 4s 5s 6s 7s 2p 3p 4p 5p 6p 3d 4d 5d 7p 6d 4f 5f  Orbital Diagram: An alternative way to write configurations

58. Pauli Exclusion Principle Pauli Exclusion Principle- at most 2 electrons per orbital…each w/ different spins

59. Electron Configuration Hund’s Rule- When electrons occupy orbitals of equal energy, they don’t pair up until they have to. Let’s determine the orbital diagram for Oxygen Need to account for 8 electrons

60. Write the orbital diagram configuration for… O N F P

61. Noble Gas Configurations For atoms with LOTS of electrons… Start off with the noble gas closest to the element Write the rest of the configuration following the noble gas EX: Ca - [Ar]4s 2

62. Noble Gas Configurations… TRY: Co Cs Cl Be Na Cu

63. Exceptions to Electron Configurations Cr and Cu

64. Chromium Chromium - 24 electrons 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 4 is expected But this is wrong!! 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 5 Why? This gives us two half filled orbitals. Slightly lower in energy. The same principal applies to copper.

65. Copper’s electron configuration Copper has 29 electrons so we expect 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 9 But the actual configuration is 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 3d 10 This gives one filled orbital and one half filled orbital. Remember these exceptions

66. PERIODIC TABLE ACTIVITY CLASS WORK

67. f orbitals start filling at 4f 12345671234567 4f 5f 3d 4d 5d 6d

68. 1s11s1 1s 2 2s 1 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 1 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6 7s 1 H 1 Li 3 Na 11 K 19 Rb 37 Cs 55 Fr 87

69. 1 st Group: all end in s 1 2 nd Group: all end in s 2 He also ends in s 2. He has the properties of the noble gases. s2s2 s1s1 S- block

70. He 2 Ne 10 Ar 18 Kr 36 Xe 54 Rn 86 1s21s2 1s 2 2s 2 2p 6 1s 2 2s 2 2p 6 3s 2 3p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 6p 6

71. The P-block p1p1 p2p2 p3p3 p4p4 p5p5 p6p6

72. Transition Metals -d block d1d1 d2d2 d3d3 d4d4 d5d5 d6d6 d7d7 d8d8 d9d9 d 10 3d 4d 5d 6d

73. F - block inner transition elements

74. Write the electron configuration for: Fe As Sr Ag P I Zn Cr S Ga