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

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

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

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

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

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

11. s and p Sub Energy Levels

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

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

15. 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

16. Sub-Energy Levels

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

18. 2 Factors Influencing Electron Placement
Energy Level
- Closer to nucleus=easy
2. Subenergy level (shape) - spdf

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

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

21. Electron Configuration PT

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

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

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

25. Noble Gas Shortcut K:
1s22s22p63s23p64s1 K:
[Ar] 4s1

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

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

28. 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?

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

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

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

32. 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

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

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

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

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

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

38. 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

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

40. 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?

41. 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?

42. 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?

43. Examples of Lewis Electron Dots

44. 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!