1. FACT:
Chemical reactions happen because electrons are shared or transferred from one substance to another

2. MAX NUMBER OF ELECTRONS IN AN ENERGY LEVEL
MAX # OF ELECTRONS 1 2 8 3 18 4 32 5 50

3. Write a mathematical equation that allows us to predict the Max # if we know the energy level (n)
Max # = …n…
ENERGY LEVEL
MAX # OF ELECTRONS 1 2 8 3 18 4 32 5 50

4. Equation to calculate Max # of e-
Where n is any energy level

5. On the Back of your Max # of Elections Sheet Bohr Models Draw the Bohr Structures for elements 1-18

6. WHITEBOARDING Bohr Models Draw the Bohr Structure for Z=19 (Potassium)

7. Catalyst Draw the Bohr Structure for Z=19 (Potassium)

8. We need a more complicated system!
Obviously something is wrong…because the electrons fill in an unexpected order.
We need a more complicated system!

9. There are 4 Quantum #s and those #s are used to describe where an electron is likely to be found at any given time

10. This is a lot like being able to use four “places” to describe EXACTLY where Mr. T should be at 8:00AM on Friday.

11. The first number we already know…
The Principle Quantum #
(b.k.a. The NRG level)

12. Specifies the energy level that the electron is on
1st Quantum #
Principle Quantum #
Specifies the energy level that the electron is on

13. Principle Quantum # (IDEA Academy’s Street)

14. But this doesn’t explain why K’s last electron goes into the 4th energy level instead of the 3rd

15. Specifies the shape of the sub-energy level
2nd Quantum #
Specifies the shape of the sub-energy level

16. Second Quantum # (IDEA Academy)

17. s and p Sub Energy Levels

18. III. Quantum Mechanical Model: Atomic Orbitals
E. Shapes of orbitals
d orbitals

20. Space occupied by a pair of electrons
ORBITAL
Space occupied by a pair of electrons

21. Four Sub-Energy Levels
Sub NRG Level
Shape
Max # of electrons
# of Orbitals s
Sphere 2 1 p
Dumbbell 6 3 d
4-Lobed 10 5 f
6-8 Lobed 14 7

22. Sub-Energy Levels

23. So why do electrons fill in like they do?
i.e. why is K’s last electron in the 4th NRG level?

24. 2 Factors Influencing Electron Placement
Energy Level
- Closer to nucleus=easy
2. Subenergy level (shape) - spdf

25. Electron Configuration
A detailed way of showing the order in which electrons fill in around the nucleus

26. Electron Configuration Symbols
# of e- in sub-energy level
5f 3
Sub-Energy Level
Energy Level

27. Electron Configuration PT

28. Bohr Models vs. e- ConfigsK K:
1s2
2s2
2p6
3s2
3p6
4s1

29. Write the e- config for:
1s1
He:
1s2
Li:
1s22s1 K:
1s22s22p63s23p64s1

30. Do Worksheet entitled “Electron Configurations”
HOMEWORK
Do Worksheet entitled
“Electron Configurations”

31. Again… Why are we concerned so much about electrons?

32. So do we really need to know about all of the electrons?

33. e- configs with the NGSC represent which electons?

34. Valence Electrons Electrons in the outermost energy level
(involved in chemical reactions)

35. Noble Gas Shortcut K: 1s22s22p63s23p64s1 K: [Ar] 4s1
So what is different?

36. Aufbau Principle
All lower energy sublevels must be full before high energy sublevels begin filling in

37. Steps for writing NGSC
Write the noble gas preceding the desired element [in brackets]
Carry on as usual

38. With only the first two Quantum #s, do we have as much information as possible as to where the electrons are likely to be found?

39. Specifies the orientation of an orbital in space
3rd Quantum #
m or magnetic Q#
Specifies the orientation of an orbital in space

40. Third Quantum # (Mr. T’s Office)

41. Spin of an electron on its own axis
4th Quantum #
s or spin Q#
Spin of an electron on its own axis

42. Fourth Quantum # (Mr. T’s Desk)

43. Quantum Review 1st Q#: Energy Level 2nd Q#: Shape of sub
3rd Q#: Orientation of Orbital
4th Q#: Spin of e-

44. Quantum Review Principle (n): 1, 2, 3, 4, … Azimuthal (l): 0, 1, 2, 3
Magnetic (ml): …-2, -1, 0, 1, 2
Spin (ms): +1/2 or -1/2

45. Pauli Exclusion Principle
No 2 electrons can have the same set of 4 quantum numbers

46. Arrow-Orbital Diagrams
A way to show orbital filling, spin, relative energy

47. Hund’s Rule
Most stable arrangement of electrons is the one with the maximum number of unpaired electrons

48. Arrow-Orbital Diagrams
Energy 3d 4s 3p 3s 2p 2s 1s

49. Lewis Electron Dot Diagrams
The easiest way to represent the # of valance electrons

50. Steps for writing electron dot diagrams
Write the element’s symbol
Write out e- config
Count # of valence e-s (1-8)
Place same # of dots as e- around symbol

51. Order to fill in an e- dot3 6 Bm 4 1 7 2 5 8

52. Why do 1 and 2 fill in on the same side?
What up? Bm 1
Who do 1 and 2 represent? 2
Why do 1 and 2 fill in on the same side?

53. Why do 3,4,5 and 6,7,8 fill in on different sides?
What up? 3 6 4 Bm
Who do 3-8 represent? 7 5 8
Why do 3,4,5 and 6,7,8 fill in on different sides?

54. Why will you never have more than eight dots?
What up? 3 6 4 Bm 1 7 2 5 8
Why will you never have more than eight dots?

55. Examples of Lewis Electron Dots

56. Our way accounts for Quantum #s, this way doesn’t!
What is different between the dot diagrams below and the ones that we’ve been doing?
Our way accounts for Quantum #s, this way doesn’t!

57.
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58. Flame Tests
Certain elements emit specific wavelengths of light when the electrons fall from outer energy levels back to their ground state.

60. The Electromagnetic Spectrum

61. Line Spectra of Excited Atoms
Excited atoms emit light of only certain wavelengths
The wavelengths of emitted light depend on the element. H Hg Ne