1. Quantum Model of the Atom Unit 5- Electrons in Atoms

2. Reminder zThomson Model - Plum Pudding z Rutherford Model - Nuclear model z1912-1913 Rutherford gathered physicists, including Neils Bohr to work on WHY atoms don’t collapse (negative e- attract positive p+)

3. Theory zPlanks Quantum Theory suggested the e- exist in energy levels that have discrete amounts of energy. ye- can jump(quantum leap) to higher levels after gaining a Quantum of energy. ySame amount of energy is given off upon return to GROUND STATE.

4. Energy Levels. zA ladder represents the idea. yLowest rung represents energy level 1, n= 1 (closest to the nucleus) yEach successive rung is a higher energy level. ( n=2, n=3, n=4…) yThe energy level is the most likely location an electron can be found within the cloud.

5. Energy Levels zn = 1 can hold 2 e- max zn = 2 can hold 8 e- max zn = 3 can hold 18 e- max zn = 4 can hold 32 e- max

6. Try these: zMg atomic number 12 (12 p+ and 12 e-) zn = 1 2 e- n = 2 8 e- n = 3 2 e-

7. Valence electrons zThe outer most electrons are called VALENCE ELECTRONS yThey are the bonding electrons – VERY IMPORTANT

8. A. Electrons as Waves zLouis de Broglie (1924) yApplied wave-particle theory to e - ye - exhibit wave properties QUANTIZED WAVELENGTHS

9. A. Electrons as Waves QUANTIZED WAVELENGTHS

10. A. Electrons as Waves EVIDENCE: DIFFRACTION PATTERNS ELECTRONS VISIBLE LIGHT

11. B. Quantum Mechanics zHeisenberg Uncertainty Principle yImpossible to know both the velocity and position of an electron at the same time

12. B. Quantum Mechanics zSchrödinger Wave Equation (1926) yfinite # of solutions  quantized energy levels ydefines probability of finding an e -

13. B. Quantum Mechanics Radial Distribution Curve Orbital zOrbital (“electron cloud”) yRegion in space where there is 90% probability of finding an e -

14. C. Quantum Numbers- Address of an e- UPPER LEVEL zFour Quantum Numbers: ySpecify the “address” of each electron in an atom

15. C. Quantum Numbers 1. Principal Quantum Number ( n ) yEnergy level ySize of the orbital yn 2 = # of orbitals in the energy level

16. C. Quantum Numbers s p d f 2. Angular Momentum Quantum # ( l ) yEnergy sublevel yShape of the orbital

17. C. Quantum Numbers zn=# of sublevels per level zn 2 =# of orbitals per level zSublevel sets: 1 s, 3 p, 5 d, 7 f

18. C. Quantum Numbers 3. Magnetic Quantum Number ( m l ) yOrientation of orbital  Specifies the exact orbital within each sublevel

19. C. Quantum Numbers pxpx pypy pzpz

20. zOrbitals combine to form a spherical shape. 2s 2p z 2p y 2p x

21. C. Quantum Numbers 4. Spin Quantum Number ( m s ) yElectron spin  +½ or -½ yAn orbital can hold 2 electrons that spin in opposite directions.

22. O 8e - zOrbital Diagram (drawing of e - location) zElectron Configuration ( distribution of e - in the orbitals) 1s 2 2s 2 2p 4 B. Notation 1s 2s 2p

23. C. Quantum Numbers 1. Principal #  2. Ang. Mom. #  3. Magnetic #  4. Spin #  energy level sublevel (s,p,d,f) orbital electron zPauli Exclusion Principle yNo two electrons in an atom can have the same 4 quantum numbers. yEach e - has a unique “address”:

24. C. Orbital Shapes S shape orbital

25. C. Orbital Shapes pxpx pypy pzpz p shaped orbitals (dumbbells)

26. C. Orbital shapes d shaped orbitals (cloverleaf)

27. E- configuration zElectrons fill the atom from Low energy to High energy. z1s 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 2 5f 14 6d 10 7p 6 zHow do we keep it straight?

28. Feeling overwhelmed? Read

29. zShorthand Configuration P 15e - Valence Electrons Core Electrons P15e - [Ne] 3s 2 3p 3 1s 2 2s 2 2p 6 3s 2 3p 3 B. Notation zLonghand Configuration

30. zShorthand Configuration Ca 20e - Valence Electrons Core Electrons Ca 20e - [Ar] 4s 2 1s 2 2s 2 2p 6 3s 2 B. Notation zLonghand Configuration 3p 6 4s 2

31. © 1998 by Harcourt Brace & Company s p d (n-1) f (n-2) 12345671234567 6767 C. Periodic Patterns

32. s-block1st Period 1s 1 1st column of s-block C. Periodic Patterns zExample - Hydrogen

33. C. Periodic Patterns zPeriod # yenergy level (subtract for d & f) zA/B Group # ytotal # of valence e - zColumn within sublevel block y# of e - in sublevel

34. A. General Rules zAufbau Principle yElectrons fill the lowest energy orbitals first.

35. A. General Rules zPauli Exclusion Principle yEach orbital can hold TWO electrons with opposite spins.

36. RIGHT WRONG A. General Rules zHund’s Rule yWithin a sublevel, place one e - per orbital before pairing them.

37. C. Periodic Patterns zShorthand Configuration yCore e - : Go up one row and over to the Noble Gas. yValence e - : On the next row, fill in the # of e - in each sublevel.