2. Apply the aufbau principle, the Pauli
exclusion principle, and Hund’s Rule to
generate electron configurations and spin
diagrams;
Explain that there can be exceptions to the
normal rules for electron configurations; and
Draw modified Bohr diagrams for atoms
3. Electron’s address
Energy level
Sublevel
Orbital
Spin
Need a system for electron addresses...
•Your address
• State
• Town
• Street
• House
4. Energy levels are numbered(1, 2, 3...)
Each energy level adds one more sublevel
(letters)
Each sublevel adds two more orbitals
Energy
Level
Sublevels and orbitals
1 s (one orb.)
2 s (one orb.), p (three orbs.)
3 s (one orb.), p (three orbs.), d (five orbs.)
4 s (one orb.), p (three orbs.), d (five
orbs.), f (seven orbs.)
5. Sublevels addressed by the number of their
energy level and letter of sublevel
◦ Example: 1s, 2s, 2p, 3s, 3p, 3d
Still two more parts to address (orbital and
spin)...
Electron configuration: arrangement of
electrons in an atom in its ground state
Orbital diagram: illustrates arrangement
and spin of electrons
6. Aufbau principle: electrons occupy orbitals
of lowest energy first
Electrons (like some students) are lazy
Orbitals in same sublevel are same energy
7. Pauli Exclusion Principle
Orbital can hold maximum
of two electrons
◦ (Two per seat on the bus)
If two electrons in an orbital,
must be opposite spins
Two possible spins: up and
down
8. Hunds Rule
Orbitals in same sublevel are same energy
Electrons fill orbitals of same energy so they
maximize same spin
Students don’t pair up in a seat until they
have to
9. One electron for every proton
Periodic table arranged by atomic number
Typewriter method: start at H, read left to
right, and stop at the element you’re
configuring
10. Further down the table...
La starts 4f sublevel
◦ Comes after 6s and before 5d
◦ Lu is actually 5d1
Ac starts 5f sublevel
◦ Comes after 7s and before 6d
◦ Lr is actually 6d1
Try some...
11. There are exceptions to the normal rules for
electron configurations
Based on stability
Just know that they exist, not how to do them
12. Atom drawn with nucleus in center and one
ring for each energy level
Electrons drawn as dots on the rings
Example: S
1s2, one ring, 2 dots
2s2, 2p6, one ring, 8 dots
3s2, 3p4, one ring, 6 dots
13. Group electrons by sublevels
Show spins
Example: S
1s2
◦ one ring, 2 arrows paired
2s2, 2p6
◦ one ring, 2 arrows paired (s), 6
arrows paired (p)
3s2, 3p4
◦ One ring, two arrows paired (s)
four arrows with two paired (p)
16 p
16n
14. Apply the aufbau principle, the Pauli
exclusion principle, and Hund’s Rule to
generate electron configurations and spin
diagrams?
Explain that there can be exceptions to the
normal rules for electron configurations?
Draw modified Bohr diagrams for atoms?
