Quantum Mechanics
Electron Configuration
Standard C:2
Students will demonstrate an understanding of atomic structure and nuclear processes.
Quantum Numbers
- Quantum numbers describe the electron in an atom.
Let's Take a Closer Look at the Quantum Numbers!
Principle Quantum Number: n
- Principal quantum number
- Represents the main energy level of an electron
- Maximum # of e- in an energy level = 2n2
- Example: What is the maximum number of electrons that can be in the 6th main energy level?
Angular Quantum Number: l
- The 2nd quantum number
- Describes the orbital shape within an energy level
- Number of orbital shapes possible in energy level = n (same as principle quantum number)
- n = 1 has 1 shape, n = 2 has 2 shapes, etc.
Orbital Shapes
Designated s, p, d, f
Level 1: s
Level 2: s, p
Level 3: s, p, d
Level 4: s, p, d, f
Electron Orbitals - s,p & d
Magnetic Quantum Number: M
- The 3rd quantum number
- Describes the orientation of the orbital in space (on x, y, or z axis)
Quantum Spin: S
- The 4th quantum number
- Describes the spin of electrons in orbitals
- Ground state: lowest energy arrangement of electrons
- spin up or spin down
Let's begin Writing Electron Configurations!
Pauli Exclusion Principle
- At the most two electron per orbital
How Many Electrons Can each Sublevel Hold?
s= 1 orbital X 2 e- / orbital = 2e-
p = 3 orbitals x 2 e- /orbital = 6 e-
d = 5 orbitals x 2 e- /orbital = 10 e-
f = 7 orbitals x 2 e- /orbital = 14 e-
Diagonal Rule (Aufbau Principle)
- Used to show the order in which electrons fill the energy levels and sublevels
- electrons enter the lowest energy level first
- Ex. H
- Ex. B
- Ex. F