1. Part One
Quantum Numbers

2. Terms to Know
Energy level/shell: describes an area that is a specific distance from the nucleus
Subshell: uniquely shaped regions at each energy level where a specific number of electrons may be found
Orbit: an area within a subshell which can hold only 2 electrons

3. Energy Level Subshell Orbit Shell Distance from nucleus
Specific shaped region within a shell
Orbit
Area within subshell which only holds 2 electrons

4. Defined Quantum numbers describe electrons.
You can think of an electron’s quantum numbers as being that electron’s address.

5. Our numbers
To describe the exact location of an electron we need 4 numbers:
Principle
Angular momentum
Magnetic
Spin

6. Principle Represented by n
Tells us how far away the electron is from the nucleus

7. How to find principle numbers
Most elements have multiple energy levels, so they have multiple principle numbers.
Period = number of energy levels
Transition metals & inner transition metals are exceptions.

8. Atom = Upside down pyramid

9. Angular Momentum Represented by l
Describes the shape of the subshell where the electron can be found
Energy levels can have multiple subshells

10. Angular Momentum
We use letters to represent the angular momentum shape:

11. Electrons per subshell
S subshells hold up to 2 electrons
P subshells hold up to 6 electrons
D subshells hold up to 10 electrons
F subshells hold up to 14 electrons
If each subshell contains orbits, and each orbit can hold 2 electrons, how many orbits are within each subshell?

12. Remember!
Hydrogen and Helium only have one energy level, but all other elements have multiple levels.
Energy levels are cumulative.
Subshell shapes are also cumulative.