1. Put the Historical Perspectives Reading Assignment on your table
Clear off everything except for a pencil, calculator (no cell phones), and periodic table
When finished the quiz, fill out BINGa sheet with elements 1-36

3. Announcements
Half of Thursday’s class will be spent in the library – independent study of the periodic table
Quiz #2 – Wed Feb. 22
Unit test – Mon Feb. 27

4. Recap What does “ground state” refer to? A. A hydrogen atom
B. Lowest energy state of an atom
C. Highest energy state of an atom
D. Minced meat
B. Lowest energy state of an atom

5. Recap How does an electron become “excited?”
A. The atom it resides in reacts with another atom
B. It absorbs energy and jumps shells
C. It absorbs specific amounts of energy and jumps shells
D. When it sees a particle of opposite charge
C. It absorbs specific amounts of energy and jumps shells

6. Recap What is a photon? A. A packet of light B. An excited proton
C. An excited electron
D. Vietnamese beef noodles stuffed inside a Chinese wonton
A. A packet of light

7. White Light Spectrum
Emission Spectrum of H

9. Recap What is an orbital?
A. The path an electron takes around the nucleus
B. Lobes
C. The shape of the nucleus
D. Mathematical description (probability) of where to find an electron in an atom
D. Mathematical description (probability) of where to find an electron in an atom

10. More About Shells
Shell 4 3 2 1

11. More About Shells
Shell 4 3 2 1
1s22s22p63s23p64s23d104p6 2 8 8 18

13. 1s 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 5d 6p 6d 7s 4f 5f

14. How did you figure out the rest of the labels
How did you figure out the rest of the labels? What do the labels represent?
The labels represent the last subshell to be filled. Every element space represents 1 electron.
Compare your labeled periodic table with the orbital energy level diagram. What do you notice?
The energy levels of the subshells correspond with the labels on the periodic table

16. Ar:
1s2
2s2
2p6
3s2
3p6
3p5
3p3
3p1
3p2
3p4

17. Ga:
1s2
2s2
2p6
3s2
3p6
4s2
3d10
4p1

18. Rn:
1s2
2s2
2p6
3s2
3p6
4s2
3d10
4p6
5s2
4d10
5p6
6s2
4f14
5d10
6p6

19. Aufbau

21. K
[Ar]
1s2 2s2 2p6 3s2 3p6
4s1
1s2 2s2 2p6 3s2 3p6 Ti
[Ar]
4s2 3d2
1s2 2s2 2p6 3s2 3p6 Ni
[Ar]
4s2 3d8
1s2 2s2 2p6 3s2 3p6 Ga
[Ar]
4s2 3d10 4p1
1s2 2s2 2p6 3s2 3p6 Kr
[Ar]
4s2 3d10 4p6 Ar

22. Core Notation
Example: Write the electron configuration for Ga using core notation.
Closest previous noble gas element: ______
Remaining configuration: _____________
Core notation: Ar
4s23d104p1
[Ar] 4s23d104p1

23. [Ar]
4s2 3d 5

24. Exceptions
There are 2 exceptions
Cr and Cu

25. What you would expect for Cr

26. In Reality

27. What you would expect for Cu

28. In Reality

29. ½ filled and completely filled subshells are more stable than partially filled subshells, and in Cr and Cu, it only takes one electron to achieve this stability in the 3d subshell
Expected
Reality Cr
[Ar] 4s23d4
[Ar] 4s13d5 Cu
[Ar] 4s23d9
[Ar] 4s13d10

30. Know the electron configuration for Cr and Cu!

31. Valence Electrons 1s2 2s22p6 3s23p6 4s1
When atoms undergo a chemical reaction, only the outermost e- are involved (furthest from nucleus and highest in energy  valence electrons

32. Electron Configuration
Valence Electrons
Valence electrons are the ones in the s and p subshells beyond the noble gas core, and any partially filled d and f subshells
Atom
Electron Configuration
# Valence e- Al Ga Pb Xe
[Ne] 3s23p1 3
[Ar] 4s23d104p1 3
[Xe] 6s24f105d106p2 4
[Kr] 5s24d105d6

33. Valence Electrons
Can you see a pattern for counting valence electrons on the periodic table?

34. Valence Electrons
Can you see a pattern for counting valence electrons on the periodic table?
# of valence e- down a group stays the same
# of valence e- of groups 1-2 are 1 and 2
# of valence e- of groups are 3-7

35. O: 1s22s22p4 O2-: ?? Negative Ions What’s changed from O to O2-?
If you had to guess where to stick the two electrons, where would they go?
O2-: ??

36. Negative Ions 1s22s22p4 + 2e-  1s22s22p6 Ne Ar 1s22s22p63s23p4 + 2e-
Add the extra electron(s) where you left off in the neutral atom
Example: Write the electron configuration for the following negative ions:
a) O2-
1s22s22p4
+ 2e- 
1s22s22p6 Ne
b) S2- Ar
1s22s22p63s23p4
+ 2e- 
1s22s22p63s23p6
c) Br- Kr
[Ar]4s23d104p5
+ 1e- 
[Ar]4s23d104p6

37. Negative Ions
Note that negative ions have the same electronic configuration as the nearest noble gas on the periodic table  isoelectronic

38. Negative Ions

39. Negative Ions
Note that negative ions have the same electronic configuration as the nearest noble gas on the periodic table  isoelectronic
If two atoms have the same electronic configuration, are they the same element?
NO!!! Remember that it is the #p that determines the element.

40. Positive Ions Sn: Sn2+: ?? 1s22s22p63s23p64s23d104p65s24d105p2
What has changed between Sn and Sn2+?
Before I ask you if you had to guess where the electrons will be removed from, where are they most definitely not removed from? Which subshells are not involved in creating a positive ion?

41. Positive Ions [Kr]5s24d105p2 - 2e-  [Kr]5s24d10 [Kr]5s24d105p2 - 4e-
Electrons in subshells with the highest n value and highest energy are removed first
Electrons are removed from the p-subshell before the s and d
Example: Write the electron configuration for the following positive ions:
a) Sn2+
[Kr]5s24d105p2
- 2e- 
[Kr]5s24d10
b) Sn4+
[Kr]5s24d105p2
- 4e- 
[Kr]4d10
c) V2+
[Ar]4s23d3
- 2e- 
[Ar]3d3

42. Let’s play BINGa!!!!!