1. Aim: How are electrons arranged in an atom?
Do Now: Please take four different colored pencils or highlighters and a Periodic Table.

2. Heisenberg Uncertainty Principal
Just remember…
It is impossible to know the precise location and velocity of an electron.

3. The Wave-Mechanical Model: Electrons exist in a cloud.

4. Dr. Niel Bohr’s Model of the Atom
Bohr stated that electrons move in principle energy levels or shells around the nucleus.
n=1
n=2
n=3
n=4
n=5
n=6
n=7

5. 1. Principle Energy Levels
Principle Energy Level (“shell”):
The region where there is the highest probability of locating an electron
Principle Quantum Number (n):
The number given to the shell or principle energy level.
Ex: n=2 refers to the 2nd shell/energy level.
On your periodic table, label the Principle Energy Levels (n).

6. On your periodic table, label the Principle Energy Levels (n).

7. On your periodic table, label the sublevels.
All principal energy levels have one or more sublevels.
Sublevels are labeled s,p,d, and f.
s<p<d<f describes the order of increasing energy.
The “n” (number of Principle Energy Levels) tells how many sublevels there are.
On your periodic table, label the sublevels.

8. On your periodic table, label the sublevels (s, p, d, and f) and color code.

9. Aim: How are electrons arranged in an atom?
Period 6 Do Now: Complete the expanded electron configurations for each of the following atoms:
Arsenic
Nickel
Rubidium

10. Principal Energy Level (n) Maximum Number of Electrons
3. Orbitals
Each orbital can hold 2 electrons.
Each sublevel has one or more orbitals. Sublevel s has 1 orbital. Sublevel p has 3 orbitals. Sublevel d has 5 orbitals. Sublevel f has 7 orbitals. (Each sublevel has two more orbitals than the previous one. Remember the first four odd #s.)
Principal Energy Level (n)
Type(s) of Sublevel
Number of Orbitals
Maximum Number of Electrons 1 s 2 p 3 6 d 5 10 4 f 7 14

11. Principal Energy Level (n) Maximum Number of Electrons
Each orbital can hold a maximum of 2 electrons.
Each sublevel has one or more orbitals.
Principal Energy Level (n)
Type(s) of Sublevel
Number of Orbitals
Maximum Number of Electrons 1 s 2 p 3 6 d 5 10 4 f 7 14

12. On your periodic table, fill in the electron numbers in each subshell.

13. Electrons always fill the orbitals always fill in a very specific pattern.
You don’t have to memorize these if you understand how the periodic table works.

14. Electrons always fill the orbitals always fill in a very specific pattern.
You don’t have to memorize these if you understand how the periodic table works.

15. 17Cl - _____________________________
Extended Electron Configuration:
Shows how many electrons are in each P.E.L. and sublevel.
Give the extended electron configuration for the following elements:
17Cl - _____________________________
9F - _______________________________
15P - ______________________________
You don’t have to memorize these if you understand how the periodic table works.

16. Noble Gas Configuration:
Shows how many electrons are in each P.E.L. and sublevel in an abbreviated format.
Give the Nobal Gas configuration for the following elements:
17Cl - _____________________________
9F - _______________________________
15P - ______________________________
You don’t have to memorize these if you understand how the periodic table works.

17. Aim: How are electrons arranged in an atom?
Period 3 Do Now: Complete the expanded electron configurations AND the noble gas configurations for each of the following atoms:
Arsenic
Nickel
Rubidium

18. As 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3 + 4d 5s 4p 3d 4s s p 1 3p 2 d 3 3s
1 2 p 1 3p 2 d 3 3s 4 5 2p 6 7 2s As f
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p3 1s +

19. Ni 1s2 2s2 2p6 3s2 3p6 4s2 3d8 + 4d 5s 4p 3d 4s s p 1 3p 2 d 3 3s 4 5
1 2 p 1 3p 2 d 3 3s 4 5 2p 6 7 2s Ni f
1s2 2s2 2p6 3s2 3p6 4s2 3d8 1s +

20. Rb 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 + 4d 5s 4p 3d 4s s p 1 3p 2 d
1 2 p 1 3p 2 d 3 3s 4 5 2p 6 7 2s Rb f
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s1 1s +

21. Hund’s Rule 1s22s22p2 2-4 Carbon
Which neutral element does this configuration represent?
Carbon

22. Pauli Exclusion Principle
1s22s22p2
2-4
An orbital pair of electrons must have opposite spins. The notation for an electron pair is...

23. 17Cl - _____________________________
Orbital Notation:
Uses up and down arrows to show the electron pairs occupying each orbital.
Give the orbital notation for the following elements:
17Cl - _____________________________
9F - _______________________________
15P - ______________________________
You don’t have to memorize these if you understand how the periodic table works.
Remember: s has 1 orbital & p has 3 orbitals.
__ __ __ __ __ __ __ __ __
1s s p s p

24. Practice Writing Bohr Electron Configuration (from reference table)
Give the Bohr electron configuration for the following elements:
17Cl - _____________________________
9F - _______________________________
15P - ______________________________
You don’t have to memorize these if you understand how the periodic table works.

25. 4d 5s 4p 3d 4s s
1 2 p 1 3p 2 d 3 3s 4 5 2p 6 7 2s Cl f
1s2 2s2 2p6 3s2 3p5 1s +