ChemCatalyst

1. ChemCatalyst • What are the three subatomic particles and their corresponding properties? • Do you think similar properties of the elements are related to subatomic particles? If yes, which one? If no, why not?

2. The Quantum Mechanical Model& Electron Configuration

3. Part 1 Models of the Atom

4. Bohr Model (old/ bio version) • Electrons move around the nucleus in fixed spherical orbits with fixed energies • Orbit: energy level designated by an integer • Electrons can go to a higher or lower energy level • Need to gain or lose a quantum of energy to get to the level above or below • Spacing between the energy levels are not even • Electrons cannot be between levels Vs

5. Atomic Emission Spectrum • This is how we know that energy gain and loss is correct • Unique for every element • Gaseous atoms emit light when subjected to an input of energy at low pressure • If you pass the light through a slit and then a prism you can separate the light into its component frequencies Barium

8. Look at Tubes • Math: • c = λν • c = speed of light = 2.998 E 8 m/s • λ = wavelength in meters • ν = frequency in 1/s (aka Hertz Hz)

10. Wave - Particle Duality All objects exhibit at times a wave - like nature, and at other times, a particle - like nature • Depends on experiment • Throws a wrench in Bohr model • New method of describing the motion of subatomic particles • Foundation of quantum mechanics

11. The Quantum Mechanical Model • What we use today • Describes location and energy of electrons • Do not have a direct orbit around the nucleus • Based on probability • Electron clouds • Electrons have quantized energy levels • This still works with atomic emission spectra and quanta

12. Hog Hilton Sample Problem • Book 15 hogs into their rooms • 6th floor ____ ____ ____ _____ _____ • 6th floor ______ • 5th floor ______ ______ ______ • 4th floor ______ • 3rd floor ______ ______ ______ • 2nd floor ______ • 1st floor ______

13. Hog Hilton Sample Problem • 3d_____ _____ _____ _____ ____ • 4s _____ • 3p ______ ______ ______ • 3s ______ • 2p ______ ______ ______ • 2s ______ • 1s ______

14. Part 2 Quantum Numbers

15. Quantum Numbers • Used to describe the location of electrons • Electrons can’t have the same quantum numbers

16. Principle Quantum Number • n • Describes energy level • Position of the electron with respect to the nucleus • As n increases = further from nucleus • Has positive values (1, 2, 3…)

17. Azimuthal Quantum Number • l • Describes the sublevel • Shape of the orbital • l = 0 = s orbital = spherical cloud • l = 1 = p orbital = dumbbell cloud • l = 2 = d orbital = clover cloud • l = 3 = f orbital = forget it! • Number of sublevels = n • Has values 0 to (n-1)

18. Shapes

19. Magnetic Quantum Number • ml • Describe the orbital and its orientation • Has values –l to l • Orbital shapes within sublevels = n2 • # of electrons = 2n2

20. Spin Quantum Number • ms • Describes the direction of the electron’s spin within a given orbital • Has a value of ½ or -½

21. Example • What orbital corresponds to n=2, l = 1 , ml = 0? • Energy level = 2 • Sublevel = p • Orbital orientation = y • Orbital = 2py

22. Quantum Numbers Sum-Up • What are the four quantum numbers and what do they indicate? • Principle Quantum Number (n): energy level • Azimuthal Quantum Number (l): sublevel and shape • Magnetic Quantum Number (ml): orientation of orbital • Spin Quantum Number (ms): direction of spin • If an element has n=3, what are the possible l values?What are the possible ml values? • l=0, 1, 2 • ml=0; ml=-1, 0, 1; ml=-2, - 1, 0, 1, 2 • What orbital corresponds to n=4 and l=2 • 4d

23. Example • What orbital corresponds to n=4, l = 2 , ml = -1? • Energy level = 4 • Sublevel = d • Orbital orientation = yz • Orbital = 4dyz

24. Putting it All Together

25. Putting it All Together

26. Part 3 Rules of Electron Configuration

27. Aufbau Principle • Electrons enter orbitals of lowest energy first • Orbitals within a sublevel have equal energy • Exceptions • Cr • Cu • Which hog rule is this?

28. Pauli Exclusion Principle • An atomic orbital may only hold two electrons • Electrons must have opposite spin • Clockwise or counterclockwise • Denoted with arrows • Prevents two electrons from having same quantum numbers • Which hog rule is this?

29. Hund’s Rule • Every orbital of the same energy is singly occupiedbefore any orbital is doubly occupied • Electrons have the same spin • Second electrons are added so the two electrons have opposite spins • Which hog rule is this?

30. Part 4 Writing Electron Configurations

31. Electron Configuration Diagonal Rule

32. Electron Orbital Diagram 3d ___ ___ ___ ___ ___ 4s ___ 3p ___ ___ ___ 3s ___ 2p ___ ___ ___ 2s ___ 1s ___

33. Filling Electron Orbitals 3d ___ ___ ___ ___ ___ 4s ___ 3p ___ ___ ___ 3s ___ 2p ___ ___ ___ 2s ___ 1s ___

34. Hog Hotel • Continue working on your hog hotel using electron configurations.

35. My Hand Hurts! • Write the electron configuration for Barium. • Wait… • Noble gas/short hand configuration: • Find the nearest noble gas that came before the element you are interested in • Write the symbol of that noble gas in [brackets] • Write the configuration as normal from there on

36. Part 5 Connecting What We’ve Learned

37. On the table • Mendeleev didn’t know quantum numbers • Table is related to how electrons fill the levels in the different shells • Blocks • s block • Groups 1 and 2 • p block • Groups 3 - 8 • d block • Transition elements • f block • Inner transition elements

39. Please complete: “Patterns in Electron Configuration”

40. Columns • Elements have similar properties • Why? • Similar ground state electron configurations • Examples • Noble gases • Complete sublevel • Favorable - do not react • Halogens • One electron short of completely filled sublevel • Readily react with elements who have a single electron