1. Orbitals and Electron Configurations
Section 6-5 to 6-8

2. Quantum Mechanics
Incorporated both wave and particle behavior of electron
Plucked guitar string
Fundamental frequency
Overtones
Mathematical wave functions
Square of wave function  probability map (orbital)

3. Orbital Shapes

4. Filling Orbitals
Aufbau Principle – electrons first fill the lowest energy orbital available
Hund’s Rule –
electrons will only pair up when there are no longer any empty orbitals in the subshell

5. Electron Configuration
For Aluminum:
1s2 2s2 2p6 3s2 3p1
Principal energy level (quantum)
Number of electrons in sublevel
Sublevel (orbital shape)

6. Orbital Diagram For Aluminum: 1s 2s 2px2py2pz 3s 3px3py3pz
Boxes represent each orbital
Electrons are shown using arrows

7. Core versus Valence Valence Electrons Electrons in the outer shell
Determine chemical properties
PT groups have same # valence e-
Core Electrons
All the inner electrons
Noble gas configuration

8. Helpful tips
Group number is the number of valence electrons for groups 1A to 8A
Element’s period gives the number of the valence shell
Number of valence electrons predict ionic charge

9. Quantum Mechanical Model
Principal quantum number, n
Angular momentum quantum number, l
0 – s
1 – p
2 – d
3 – f
Magnetic quantum number, ml
Ranges from –l to l

10. Electron Spin Spin magnetic quantum number, ms + 1 2 or - 1 2
Pauli Exclusion Principle
orbital holds max of 2 electrons with opposite spins

12. Electron shell –
all orbitals with same value of n
Subshell –
all orbitals with same value of n and l
Shell has n subshells
Subshell has 2 L + 1 orbitals
Shell has n2 orbitals

13. Radial probability function – shows probability of finding the electron at certain distance from nucleus

14. PRACTICE Write the electron configuration forCr U
Write the orbital diagram for N F
List the number of valence electrons for each element in 1 and 2
Identify the quantum numbers for the valence electrons for each element in 2