1. WARM UP Write electron configurations for the following atoms (hint: 2, 8, 8, 18, etc.). Iron (26 e - ) Uranium (92 e - ) Potassium (18 e - )

2. Periodic Table and Electron Configurations

3. Inner Core Electrons Inner shells –Ignored

4. Valence Electrons Electrons in the atom’s outermost shell –Important!

5. Periods and Valence Shell Each period represents one shell –The period you are in is your outermost shell Ex: Mn= 4 shellsPb= 6 shellsU= 7 shells

6. Groups and Valence e - Count across to find how many e - are in valence shell –Ex: Mn = 7Pb = 28U = 6

7. Noble Gas Notation Shows valence e - only –Inner e - shortened to noble gas 2,8 = Ne………………….Aluminum = [Ne] 3 2,8,8 = Ar…………………………Bromine = [Ar] 17

8. Noble Gas Notation Steps to write 1.Write preceding noble gas 2.Count boxes across in next period Ex. Fr and Ge

9. WRAP UP Identify the valence shell for: Mg U Xe Identify the # of e- in the valence shell for: C Pb Ge In