2. Unit 3: Part 2 Electron Configurations

3. Quantum Theory  Developed over many years involving many experiments:  Max Plank (1900) First introduced idea that light came in “quanta” packets of energy instead of continuous flow.  Einstein (1905) proposed that light and matter interact; light can stimulate electric flow in metals. He proposed the “Photoelectric Effect.”  Niels Bohr: developed the quantum theory of the Atom; he first proposed that electrons can only absorb Specific “quanta” of energy. He also proposed that electrons can only Occupy specific energy levels around the nucleus. See next page: Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem Max Planck

4. We have learned about basic atomic structure regarding protons, neutrons electrons. What we know so far: Atom contain a dense, positively charged nucleus (Rutherford’s Experiment) Neutrally charged particles called neutrons are located in nucleus. (prevents coulomb repulsion of protons. Electrons located outside nucleus; very small mass. The field of chemistry deals with ELECTRONS and how they move between atoms. THIS IS THE HEART OF CHEMISTRY. WE WILL FOCUS ON ELECTRONS THE REST OF THE YEAR.

6. Bohr Model Electrons exist only in orbits with specific amounts of energy called energy levels Therefore… electrons can only gain or lose certain amounts of energy (photons or packets of light) only certain photons are produced Link to Animation of Bohr Model Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

7. Quantum Address: In Bohr’s model, each electron is assigned a quantum “address” and no two electrons can occupy the same address/position. There are four “quantum” numbers that describe an electron’s “address” These numbers are discussed on the next page.

8. Quantum Numbers n shell l subshell m l orbital m s electron spin 1, 2, 3, 4,... 0, 1, 2,... n - 1 - l... 0... +l + 1 / 2 and - 1 / 2 But what do these numbers mean? Continue on……….

9.  n stands for Principle quantum number (describes the distance the energy level is from the nucleus. Can be 1 through 7)  l stands for Angular momentum number; describes the sublevel the electron is found in (s,p,d or f) within an energy level (n).  M l stands for Magnetic quantum number; this provides information about which “box” or “circle” the electron is located within the sublevel (l).  M s stands for Spin Quantum number; provides information about the direction of the wave. (Note: spin is a complex topic. We show spin by using an “UP” or “Down” arrow in each sublevel box (Ml).  Please follow this link for an in-depth discussion of Quantum Numbers Please follow this link for an in-depth discussion of Quantum Numbers

10. Spin Quantum Number, m s North South The electron behaves as if it were spinning about an axis through its center. This electron spin generates a magnetic field, the direction of which depends on the direction of the spin. -- S N Electron aligned with magnetic field, m s = + ½ Electron aligned against magnetic field, m s = - ½

11. Filling Rules for Electron Orbitals Aufbau Principle: Electrons are added one at a time to the lowest energy orbitals available until all the electrons of the atom have been accounted for. Pauli Exclusion Principle: An orbital can hold a maximum of two electrons. To occupy the same orbital, two electrons must spin in opposite directions. Hund’s Rule: Electrons occupy equal-energy orbitals so that a maximum number of unpaired electrons results. *Aufbau is German for “building up”

12. General Rules Pauli Exclusion PrinciplePauli Exclusion Principle –Each orbital can hold TWO electrons with opposite spins. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem Wolfgang Pauli

13. General Rules Aufbau Principle –Electrons fill the lowest energy orbitals first. –“Lazy Tenant Rule” Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem 2s2s 3s3s 4s4s 5s5s 6s6s 7s7s 1s1s 2p2p 3p3p 4p4p 5p5p 6p6p 3d3d 4d4d 5d5d 6d6d 4f4f 5f5f 1s1s 2s2s 2p2p 3s3s 3p3p 4s4s 4p4p 3d3d 4d4d 5s5s 5p5p 6s6s 7s7s 6p6p 6d6d 4f4f 5f5f 5d5d Energy

14. RIGHT WRONG General Rules Hund’s RuleHund’s Rule –Within a sublevel, place one electron per orbital before pairing them. –“Empty Bus Seat Rule” Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

15. H = 1s 1 1s1s He = 1s 2 1s1s Li = 1s 2 2s 1 1s1s 2s2s Be = 1s 2 2s 2 1s1s 2s2s C = 1s 2 2s 2 2p 2 1s1s 2s2s 2px2px 2py2py 2pz2pz S = 1s 2 2s 2 2p 4 1s1s 2s2s 2px2px 2py2py 2pz2pz 3s3s 3px3px 3py3py 3pz3pz THIS SLIDE IS ANIMATED IN FILLING ORDER 2.PPTFILLING ORDER 2.PPT

16. H = 1s 1 1s1s He = 1s 2 1s1s Be = 1s 2 2s 2 1s1s 2s2s +1 e-e- +2 e-e- e-e- +4 e-e- e-e- e-e- e-e- Coulombic attraction holds valence electrons to atom. Valence electrons are shielded by the kernel electrons. Therefore the valence electrons are not held as tightly in Be than in He.

17. Maximum Number of Electrons In Each Sublevel Maximum Number of Electrons In Each Sublevel Maximum Number SublevelNumber of Orbitals of Electrons s 1 2 p 3 6 d 5 10 f 7 14 LeMay Jr, Beall, Robblee, Brower, Chemistry Connections to Our Changing World, 1996, page 146

18. Fe = 1s 1 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 1s1s 2s2s 2px2px 2py2py 2pz2pz 3s3s 3px3px 3py3py 3pz3pz +26 e-e- e-e- e-e- e-e- 4s4s 3d3d 3d3d3d3d 3d3d Iron has ___ electrons. 26 3d3d Arbitrary Energy Scale 18 32 8 8 2 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e- e-e-

19. Orbital Filling Element 1s 2s 2p x 2p y 2p z 3s Configuration Orbital Filling Element 1s 2s 2p x 2p y 2p z 3s Configuration Electron Configurations Electron H He Li C N O F Ne Na 1s 1 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 1s 2 2s 2 2p 5 1s 2 2s 2 2p 4 1s 2 2s 2 2p 3 1s 2 2s 2 2p 2 1s 2 2s 1 1s 2 NOT CORRECT Violates Hund’s Rule Electron Configurations Electron H He Li C N O F Ne Na 1s 1 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 1s 2 2s 2 2p 5 1s 2 2s 2 2p 4 1s 2 2s 2 2p 3 1s 2 2s 2 2p 2 1s 2 2s 1 1s 2

20. Orbital Filling Element 1s 2s 2p x 2p y 2p z 3s Configuration Electron Configurations Electron H He Li C N O F Ne Na 1s 1 1s 2 2s 2 2p 6 3s 1 1s 2 2s 2 2p 6 1s 2 2s 2 2p 5 1s 2 2s 2 2p 4 1s 2 2s 2 2p 3 1s 2 2s 2 2p 2 1s 2 2s 1 1s 2

21. Energy Level Diagram of a Many-Electron Atom Arbitrary Energy Scale 18 32 8 8 2 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS O’Connor, Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles  1982, page 177

22. Quantum Numbers n shell l subshell m l orbital m s electron spin 1, 2, 3, 4,... 0, 1, 2,... n - 1 - l... 0... +l + 1 / 2 and - 1 / 2

23. Electrons in n = 5 shell What is the maximum shell population of n = 5? n = 5 l = 0(s) l = 1(p) l = 2(d) l = 3(f) m l = 0 m l = 1 m l = 0 m l = -1 A - 50 (2+6+10+14+18) l = 4 has 9 orbitals: it has 18 electrons or 2(5) 2 = 50 l = 4(g) m s = ½ m s = - ½ m s = ½ m s = - ½ m s = ½ m s = - ½ m s = ½ m s = - ½ ½

24. Electron Configuration Filling-Order of Electrons in an Atom

25. Order in which subshells are filled with electrons 1s2s3s4s5s6s7s1s2s3s4s5s6s7s 2p3p4p5p6p 2p3p4p5p6p 3d4d5d6d 3d4d5d6d 4f5f 4f5f 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d … 2 2 6 2 6 2 10 6 2 10

26. 4f4f 4d4d 4p4p 4s4s n = 4 3d3d 3p3p 3s3s n = 3 2p2p 2s2s n = 2 1s1s n = 1 Energy Sublevels 2s2s 3s3s 4s4s 5s5s 6s6s 7s7s 1s1s 2p2p 3p3p 4p4p 5p5p 6p6p 3d3d 4d4d 5d5d 6d6d 4f4f 5f5f 1s1s 2s2s 2p2p 3s3s 3p3p 4s4s 4p4p 3d3d 4d4d 5s5s 5p5p 6s6s 7s7s 6p6p 6d6d 4f4f 5f5f 5d5d Energy

27. 4f4f 4d4d 4p4p 4s4s n = 4 3d3d 3p3p 3s3s n = 3 2p2p 2s2s n = 2 1s1s n = 1 Energy Sublevels s s s s p p p d df 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 …

28. Filling Rules for Electron Orbitals Aufbau Principle: Electrons are added one at a time to the lowest energy orbitals available until all the electrons of the atom have been accounted for. Pauli Exclusion Principle: An orbital can hold a maximum of two electrons. To occupy the same orbital, two electrons must spin in opposite directions. Hund’s Rule: Electrons occupy equal-energy orbitals so that a maximum number of unpaired electrons results. *Aufbau is German for “building up”

29. Energy Level Diagram of a Many-Electron Atom Arbitrary Energy Scale 18 32 8 8 2 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS O’Connor, Davis, MacNab, McClellan, CHEMISTRY Experiments and Principles  1982, page 177

30. Electron capacities Copyright © 2006 Pearson Benjamin Cummings. All rights reserved. Electron capacities

37. Copyright © 2006 Pearson Benjamin Cummings. All rights reserved.

38. Copyright © 2007 Pearson Benjamin Cummings. All rights reserved. 32 18 8 8 2

39. Copyright © 2007 Pearson Benjamin Cummings. All rights reserved.

40. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N HH He Li C N Al Ar F Fe LaHeLiCNAlArFFeLa

41. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N H = 1s 1 Hydrogen H He Li C N Al Ar F Fe LaHeLiCNAlArFFeLa

42. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N He = 1s 2 Helium HH He Li C N Al Ar F Fe LaLiCNAlArFFeLa

43. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N Li = 1s 2 2s 1 Lithium HH He Li C N Al Ar F Fe LaHeCNAlArFFeLa

44. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N C = 1s 2 2s 2 2p 2 Carbon HH He Li C N Al Ar F Fe LaHeLiNAlArFFeLa

45. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N N = 1s 2 2s 2 2p 3 Bohr Model Nitrogen Hund’s Rule “maximum number of unpaired orbitals”. HH He Li C N Al Ar F Fe LaHeLiCAlArFFeLa

46. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N F = 1s 2 2s 2 2p 5 Fluorine HH He Li C N Al Ar F Fe LaHeLiCNAlArFeLa

47. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Bohr Model Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N Al = 1s 2 2s 2 2p 6 3s 2 3p 1 Aluminum HH He Li C N Al Ar F Fe LaHeLiCNArFFeLa

48. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS Electron Configuration CLICK ON ELEMENT TO FILL IN CHARTS N Ar = 1s 2 2s 2 2p 6 3s 2 3p 6 Bohr Model Argon HH He Li C N Al Ar F Fe LaHeLiCNAlFFeLa

49. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS CLICK ON ELEMENT TO FILL IN CHARTS Fe = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 N HH He Li C N Al Ar F Fe LaHeLiCNAlArFLa Bohr Model Iron Electron Configuration

50. Energy Level Diagram Arbitrary Energy Scale 1s 2s 2p 3s 3p 4s 4p 3d 5s 5p 4d 6s 6p 5d 4f NUCLEUS CLICK ON ELEMENT TO FILL IN CHARTS La = 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 5d 1 N HH He Li C N Al Ar F Fe LaHeLiCNAlArFFe Bohr Model Lanthanum Electron Configuration

51. neon's electron configuration (1s 2 2s 2 2p 6 ) Shorthand Configuration [Ne] 3s 1 third energy level one electron in the s orbital orbital shape Na = [1s 2 2s 2 2p 6 ] 3s 1 electron configuration A B C D

52. Shorthand Configuration [Ar] 4s 2 Electron configurationElement symbol [Ar] 4s 2 3d 3 [Rn] 7s 2 5f 14 6d 4 [He] 2s 2 2p 5 [Kr] 5s 2 4d 9 [Kr] 5s 2 4d 10 5p 5 [Kr] 5s 2 4d 10 5p 6 [He] 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 Ca V Sg F Ag I Xe Fe [Ar] 4s 2 3d 6

53. O 8e - Orbital Diagram Electron Configuration 1s 2 1s 2 2s 2 2s 2 2p 4 Notation 1s 2s 2p Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem O 15.9994 8

54. Shorthand Configuration S 16e - Valence Electrons Core Electrons S16e - [Ne] 3s 2 3p 4 1s 2 2s 2 2p 6 3s 2 3p 4 Notation Longhand Configuration Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem S 32.066 16

55. s p d (n-1) f (n-2) 6767 Periodic Patterns 1s1s1s1s 2s2s2s2s 3s3s3s3s 4s4s4s4s 5s5s5s5s 6s6s6s6s 7s7s7s7s 3d3d3d3d 4d4d4d4d 5d5d5d5d 6d6d6d6d 1s1s1s1s 2p2p2p2p 3p3p3p3p 4p4p4p4p 5p5p5p5p 6p6p6p6p 7p7p7p7p 4f4f4f4f 5f5f5f5f 12345671234567

56. Period # –energy level (subtract for d & f) A/B Group # –total # of valence e - Column within sublevel block –# of e - in sublevel Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

57. s-block1st Period 1s 1 1 st column of s-block Periodic Patterns Example - Hydrogen Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

58. Periodic Patterns Shorthand Configuration –Core electrons: Go up one row and over to the Noble Gas. –Valence electrons: On the next row, fill in the # of e - in each sublevel. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

59. [Ar]4s 2 3d 10 4p 2 Periodic Patterns GermaniumExample - Germanium Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem Ge 72.61 32

60. Full energy level Full sublevel (s, p, d, f) Half-full sublevel Stability Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

61. This fills the valence shell and tends to give the atom the stability of the inert gasses. The Octet Rule Atoms tend to gain, lose, or share electrons until they have eight valence electrons. 8 sp ONLY s- and p-orbitals are valence electrons.

62. Electron Configuration Exceptions –Copper EXPECT :[Ar] 4s 2 3d 9 ACTUALLY :[Ar] 4s 1 3d 10 –Copper gains stability with a full d-sublevel. Stability Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

63. Electron Configuration Exceptions –Chromium EXPECT :[Ar] 4s 2 3d 4 ACTUALLY :[Ar] 4s 1 3d 5 –Chromium gains stability with a half-full d-sublevel. Stability Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

64. Electron Filling in Periodic Table K4s1K4s1 Ca 4s 2 Sc 3d 1 Ti 3d 2 V3d3V3d3 Mn 3d 5 Fe 3d 6 Co 3d 7 Ni 3d 8 Cr 3d 4 Cu 3d 9 Zn 3d 10 Ga 4p 1 Ge 4p 2 As 4p 3 Se 4p 4 Br 4p 5 Kr 4p 6 1 2 3 4 s d p s Cr 4s 1 3d 5 Cu 4s 1 3d 10 4f4f 4d4d 4p4p 4s4s n = 4 3d3d 3p3p 3s3s n = 3 2p2p 2s2s n = 2 1s1sn = 1 Energy 4s3d Cr 4s 1 3d 5 4s3d Cu 4s 1 3d 10 Cr 3d 5 Cu 3d 10

65. Stability Ion Formation –Atoms gain or lose electrons to become more stable. –Isoelectronic with the Noble Gases. Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

66. O 2- 10e - [He] 2s 2 2p 6 Stability Ion Electron Configuration –Write the e - configuration for the closest Noble Gas EX: Oxygen ion  O 2-  Ne Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

67. Electron Configurations Keys Electron Configuration WSElectron Configuration WS PatternPattern Electron Configuration WSElectron Configuration WS PatternPattern http://www.unit5.org/chemistry/Atom.html

68. Orbital Diagrams for Nickel 2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s 2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s Excited State Pauli Exclusion Hund’s Rule Ni 58.6934 28 2 2 6 2 6 2 8 2 2 6 2 6 1 9

69. Orbital Diagrams for Nickel 2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s 2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s Excited State VIOLATES Pauli Exclusion VIOLATES Hund’s Rule Ni 58.6934 28 2 2 6 2 6 2 8 2 2 6 2 6 1 9

70. Write out the complete electron configuration for the following: 1) An atom of nitrogen 2) An atom of silver 3) An atom of uranium (shorthand) Fill in the orbital boxes for an atom of nickel (Ni) 2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s Which rule states no two electrons can spin the same direction in a single orbital? Extra credit: Draw a Bohr model of a Ti 4+ cation. Ti 4+ is isoelectronic to Argon. POP QUIZ

71. Write out the complete electron configuration for the following: 1) An atom of nitrogen 2) An atom of silver 3) An atom of uranium (shorthand) Fill in the orbital boxes for an atom of nickel (Ni) 2s2s2p2p 3s3s 3p3p4s4s3d3d1s1s Which rule states no two electrons can spin the same direction in a single orbital? 1s 2 2s 2 2p 3 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 9 [Rn]7s 2 6d 1 5f 3 Extra credit: Draw a Bohr model of a Ti 4+ cation. 22+ n = n Pauli exclusion principle Ti 4+ is isoelectronic to Argon. Answer Key