1. Warm-Up
UV Radiation is always emitted when an electron falls back to which energy level?
What color of light is emitted when an electron falls from n = 6 to n = 2?

2. Quantum Numbers

3. Quantum Numbers
4 different numbers to identify one specific electron in an atom
Distance of orbital from the nucleus
Shape of the orbital
Orientation of the orbital
Spin of the electron in the orbital

4. Principal Quantum Number (n)
Indicates main energy level around the nucleus
Possible values: 1, 2, 3, 4, 5, … (integers)
n = 1 is closest to the nucleus and has the lowest energy

5. Orbital Quantum Number (l)
Indicates shape of orbital
Each energy level has different sublevels which are differentiated by their shapes
Number of sublevels = n
Possible values: 0 to (n-1)
Possible orbital types: s, p, d, f (lowest to highest energy)

6. Orbital Types
Energy Level n l
Orbital Type

7. Orbital A region occupied by a maximum of 2 electrons
As the number of energy levels increases, there are more orbitals
# of orbitals in a main energy level = n2
Degenerate Orbitals – orbitals that have identical energies

8. Magnetic Quantum Number (ml)
Describes orientation of the orbital about the nucleus (position)
Possible values: -l to +l
Orbital Type l
Orbital Shape
# of Orientations
Notations

9. s Orbitals

10. p Orbitals

11. d Orbitals

12. f Orbitals

13. Spin Quantum Number (ms)
Indicates state of electron (direction of spin)
Counterclockwise (Up) or Clockwise (Down)
Only two possible values: +½ and -½

14. Pauli Exclusion Principle
No two electrons can have the same set of 4 quantum numbers ever!!!
If two electrons are in the same orbital, they must have opposite spins!

15. Warm-Up
*Pick up the handouts from the front. WITHOUT looking at your notes answer as many of the questions on the Quantum Numbers Practice as you can.