1. Electron Orbitals and Orbital Filling Diagrams

2. Remember the Bohr Atom
We can simplify this diagram…

3. Representing Energy Levels
Energy levels going away from nucleus.
Nucleus down here

4. Energy Levels Within Atom
Within each energy level, there are sub-levels called orbitals. Each energy level has a different number of sub-levels.
n=4 d
n=3 p s E p
Sublevels
n=2 s
n=1 s
Principle Energy Levels (n)

5. Orbitals
Orbitals given designations: s p d f

6. Orbitals
Orbitals: specific defined space that there is a high probability of finding the electron(s)
s p d

7. Brain Break: Your Choice for 30 seconds
Arm Circles
Squats
Lunges
Wall Sit
Punches
Skier
Jog in Place
Inclined Push-Ups
Other

8. Another way we represent electrons in an atom is by the electron configuration.
There are a couple of methods we can use to write out an electron configuration.
Orbital Filling diagrams
From the periodic table
Orbital boxes
Noble Gas Notation

9. Orbital Filling Diagram
Determine the number of electrons the atom has.
Start at the lowest energy level and fill up. (Aufbau principle)
Only two electrons per orbital. (Pauli exclusion principle.)
For the p, d, and f orbitals, fill each degenerate level with one electron, then go back and add more. (Hund’s rule).
Once the diagram is filled, condense the diagrams to write out the electron configuration.

10. Example
Complete this diagram for the element, Arsenic (As)

11. Example
Complete this diagram for the element, Potassium (K)

12. On Your Paper… Mg Al H C Cl Ne

13. Electron Configurations
• shorthand method of representing electron filling
• the “address” of the e-’s in an atom
• determined by filling order (Aufbau, Pauli exclusion, Hund’s rule)

14. Electron Configurations
# of electrons
Example: Nitrogen 1s22s22p3
Orbital type (or sublevel)
Energy level

15. Electron Configurations
Note: • energy levels included with every orbital!
• use lower case letters for orbital types (3p NOT 3P)
• # of e- in orbital --> superscript