1. Electron Configuration

2. Activity Make three large sheets with a different element on each.
Each sheet will have electron configuration, Bohr model with dots, and orbital diagram of that element.
Students will do a gallery walk and put sticky notes under three categories; I know, I wonder, I discovered.

3. Simple model of a potassium atom
Electron Structure
In a neutral atom, electrons = atomic number.
Electrons are arranged into energy levels.
Energy Level (shell) defines how far the electron is away from the nucleus.
n = 1
n = 3
n = 4
More Energy
Nucleus
n = 2
Simple model of a potassium atom

4. Quantum Numbers 4 numbers that define the location and movement of the electrons.
Principle Quantum number (n)
Orbital Angular Momentum Quantum number (l)
Magnetic Quantum number (ml)
Spin Quantum number (ms)

5. Principle Quantum number (n) = Energy Level (shell) defines how far the electron is away from the nucleus.

6. Orbitals Shells are divided into subshells (orbitals).
Orbital Angular momentum quantum number (l) – defines the shape of the sublevel (orbital).
Four types: (named after spectroscopic groups of lines before quantum mechanics)
Energy Level (shell) (angular momentum)
s (sharp) (l=0)
p (principal) (l=1)
d (diffuse) (l=2)
f (fundamental) (l=3)

7. Magnetic quantum number (ml) – defines the orientation in space of the orbital.
s, p, d, and f orbitals

8. Electron Spin
Spin Quantum number (ms) – designates direction of electron spin.
Each orbital can hold up to 2 electrons.
Why only 2 in each orbital?
Spin up
Spin down
Stern-Gerlach Experiment

9. Video
Video – Electron Spin Explained

10. Electron Structure n=1 n=2 n=3 n=4 s l=0 1s 2s 3s 4s p l=1 2p 3p 4p
Shells and orbitals
n=1 n=2 n=3 n=4
s l= s 2s 3s 4s
p l=1 2p 3p 4p
d l= d 4d
f l= f

11. Electron Structure Orbitals s / 1 orbital / 2 electrons
p / 3 orbitals / 6 electrons
d / 5 orbitals / 10 electrons
f / 7 orbitals / 14 electrons

12. Electron Configurations3p 3d 4d 5d 6d 2p 4p 5p 6p 7p 4f 5f
1st row
2nd row
3rd row
4th row
5th row
6th row
7th row
Row number – 1
Row number – 2

13. Electron Configurations
What is the electron configuration for H?
H has 1 e-
What is the electron configuration for He?
He has 2 e-
1s1
1s2

14. Electron Configurations
What is the e- config. for lithium?
What is the e- config. for oxygen?
1s2
2s1
1s2
2s2
2p4

15. Electron Configuration Practice thru period 3 Board

16. Electron Structure
Aufbau Principle – Electrons fill lowest sublevels first.
Aufbau = German for “building up”.
Energy levels overlap.
Expected order:
1s 2s 2p 3s 3p 3d 4s 4p 4d 4f...
Actual order:
1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f...

17. Aufbau Principle 6p 5d 4f 6s 5p 4d 5s 4p Increasing Energy 3d 4s 3p 3s

18. Electron Configurations3p 3d 4d 5d 6d 2p 4p 5p 6p 7p 4f 5f
1st row
2nd row
3rd row
4th row
5th row
6th row
7th row
Row number – 1
Row number – 2

19. Electron Configuration1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 7s 7p

20. Electron Configurations
What is the e- config. for iron?
What is the e- config. for iodine?
1s2
2s2
2p6
3s2
3p6
4s2
3d6
1s2
2s2
2p6
3s2
3p6
4s2
3d10
4p6
5s2
4d10
5p5

21. Electron Configuration Practice after period 3 Board

22. Noble Gas Configuration
Noble gases: Group 8A
He, Ne, Ar, Kr, Rn, Xe, element 118
e- configuration for Mg (element 12):
1s2 2s2 2p6 3s2
e- configuration for Ne (element 10):
1s2 2s2 2p6
Noble gas configuration for Mg:
[Ne] 3s2

23. Noble Gas Configuration
To write NGC:
Find your element.
Find the noble gas (Group 8A) before your element.
Write the noble gas in brackets.
Add electrons to the noble gas until you reach your element.

24. Noble Gas Configuration
Write the NGC for bismuth (element 83)
Previous noble gas: xenon (element 54)
Bismuth is on row 6, so start with 6s2.
Brings the total up to 56.
Proceed to 4f14.
Brings the total up to 70.
Proceed to 5d10.
Brings the total up to 80.
Proceed to 6p3.
Brings the total up to 83.
Done!
[Xe]
6s2
4f14
5d10
6p3

25. Noble Gas Configuration
Write the NGC for radium (element 88)
Previous noble gas: radon (element 86)
Radium is on row 7, so start with 7s2
Brings the total up to 88.
Done!
[Rn]
7s2

26. Noble Gas Configuration Practice Board

27. Configuration Practice Sheet