2. Noble Gas Configuration  NOBLE GASES: The far right column of the periodic table  The s & p sublevels are filled  Very stable elements  Example: Neon = 1s 2 2s 2 2p 6 Argon = 1s 2 2s 2 2p 6 3s 2 3p 6 Electron Configuration 5.3

3. Noble Gas Configuration  Shorthand electron configuration  Symbol of the noble gas in the previous energy level in brackets  Plus the electron configuration for the remaining energy level  Example: Sulfur = 1s 2 2s 2 2p 6 3s 2 3p 4 [Ne]3s 2 3p 4 Electron Configuration 5.3

4. Noble Gas Configuration  PRACTICE: Na Mg Al Ca Br Electron Configuration 5.3 [Ne]3s 1 [Ne]3s 2 [Ne]3s 2 3p 1 [Ar]4s 2 [Ar]4s 2 3d 10 4p 5

5. Valence Electrons  Valence electrons: found in the outermost energy level (sometimes called a shell)  Located in highest s and p sublevels  These electrons are used for bonding  Example: Nitrogen = 1s 2 2s 2 2p 3  So, nitrogen has 2 + 3 = 5 valence electrons Electron Configuration 5.3

6. Noble Gas Configuration  PRACTICE:# Valence e- Na[Ne]3s 1 Mg[Ne]3s 2 Al[Ne]3s 2 3p 1 Ca[Ar]4s 2 Br[Ar]4s 2 3d 10 4p 5 Electron Configuration 5.3 1 2 3 2 7

7. Lewis-Dot Diagrams  Lewis Dot Diagrams are a way to represent the valence electrons in an atom.  Dots around the element symbol represent the valence electrons  Maximum of 8 e- around the symbol: OCTET RULE  in s or p sublevels only  Sulfur = 1s 2 2s 2 2p 6 3s 2 3p 4 6 valence electrons Electron Configuration 5.3

8. Noble Gas Configuration Write the Noble Gas Configuration and Lewis Dot Structures for these elements: LiOSiPK SeSrIBaPb Electron Configuration 5.3