1. s – Sphere p – Dumbbell d – Clover f - ??? Probability & Orbitals
Atomic Orbitals :
Plot of Ψ = region (or shape) around the nucleus of an atom where an electron with a given energy is likely  (90%) to be found.
Orbital Shapes
s – Sphere
p – Dumbbell
d – Clover
f - ???

2. s p d f (low energy e- to high energy e-)
Orbitals & Energy
The amount of energy that an electron has determines the kind of orbital it occupies.
s p d f (low energy e- to high energy e-)
The energy of an electron increases as n (quantum number 1,2,3,4…)  increases.
Each quantum or energy level can be divided into sublevels
# of sub-levels = # of orbitals (s,p,d,f) per energy level
The # of sublevels in each energy level = the quantum number squared (n2)
Energy Level (n)
# of Sublevels (n2)
Energy Level
Orbital shape 1
1 :1s (one circular orbital) 2
4 :2s (one circular) & 2p (three dumbell) 3
9 :3s (one circular) & 3p (three dumbell) & 3d (five clover) 4
16 :4s (one circular) & 4p (three dumbell) & 4d (five clover) & 4f (seven ????)

3. Orbital Diagrams & Electron Configurations
Orbital Diagram –visual method of organizing an atom’s electrons in different energy levels and orbitals.
Aufbau Principle – electrons enter the orbital of lowest energy level and sublevel available first.       
Pauli Exclusion Principle – Each orbital can hold at maximum 2 electrons with opposite spins (cancel magnetic fields).
1 clockwise ( + ½)   & 1 counter clockwise (- ½)
Hund’s Rule – Before an electron can be placed in an orbital, all of the orbitals of that sub-level must have at least one electron.
Electron Configuration:  the address of electrons in an atom.  

4. Valence vs. Core Electrons
Valence Level: the highest (furthest from the nucleus) energy level (n=1, n=2…..)
Valence Electrons:  electrons in the s and p orbitals in the highest energy level
1s22s22p63s23p64s2
Octet :   8 valence electrons (full s and p orbitals in the highest energy level)
** Elements with an Octet are chemically stable!
** Will not react with other matter
1s22s22p63s23p6
Core Electrons: All other electrons in the configuration beside valence electrons
            1s22s22p63s23p64s2               

5. [Ne] 3s2 3p6 Short Hand Electron Configuration
Write symbol in brackets of [noble gas] (last column on the right of the periodic table) before element.
Write the configuration from noble gas to your element!
For Carbon – 6 electrons : Long Hand –  1s2 2s2 2p2 Short Hand    [He] 2s2 2p2
For Calcium – 20 electrons : Long Hand –   1s2 2s2 2p63s2 3p64s2 Short Hand -   [Ar] 4s2
For Argon – 18 electrons:
Long Hand - 1s2 2s2 2p63s2 3p6
Short Hand – [Ar] ?
[Ne] 3s2 3p6

6. The 4 Orbital “Blocks” on the Periodic Table

7. Ions & Electron Configurations
What is lowest Ionization Energy path to octet?
IE = energy needed to remove valence electron
Sodium – Na (IE = V) s22s22p63s1
Sodium ion – Na s2 2s2 2p6
Fluorine – F (IE = V) s22s22p5
Fluorine ion – F s22s22p6
Isoelectric – ions with the same electron configuration as their nearest noble gas.