1. Electron Configuration Electrons in Atoms

2. A. General Rules zPauli Exclusion Principle yEach orbital can hold TWO electrons with opposite spins.

3. A. General Rules zAufbau Principle yElectrons fill the lowest energy orbitals first. y“Lazy Student Rule” (no elevator)

4. RIGHT WRONG A. General Rules zHund’s Rule yWithin a sublevel, place one e - per orbital before pairing them. y“ One student per room before roommate”

5. O 8e - zOrbital Diagram zElectron Configuration 1s 2 2s 2 2p 4 B. Notation 1s 2s 2p

6. © 1998 by Harcourt Brace & Company s p d (n-1) f (n-2) 12345671234567 6767 C. Periodic Patterns

7. zPeriod # yenergy level (subtract for d & f) zA/B Group # ytotal # of valence e - zColumn within sublevel block y# of e - in sublevel

8. s-block1st Period 1s 1 1st column of s-block C. Periodic Patterns zExample - Hydrogen