1. Electron Configuration Electrons in Atoms Adapted from Christy Johannesen http://www.nisd.net/communicationsarts/pages/chem/notes.htm#atom http://www.nisd.net/communicationsarts/pages/chem/notes.htm#atom

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. yLazy Tenant Rule

4. RIGHT WRONG A. General Rules zHunds Rule yWithin a sublevel, place one e - per orbital before pairing them. yEmpty Bus Seat Rule

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

6. zShorthand Configuration S 16e - Valence Electrons Core Electrons S16e - [Ne] 3s 2 3p 4 1s 2 2s 2 2p 6 3s 2 3p 4 B. Notation zLonghand Configuration

7. © 1998 by Harcourt Brace & Company s p d (n-1) f (n-2) 12345671234567 6767 C. Periodic Patterns

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

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

10. C. Periodic Patterns zShorthand Configuration yCore e - : Go up one row and over to the Noble Gas. yValence e - : On the next row, fill in the # of e - in each sublevel.

11. [Ar]4s 2 3d 10 4p 2 C. Periodic Patterns zExample - Germanium

12. zFull energy level zFull sublevel (s, p, d, f) zHalf-full sublevel D. Stability

13. zElectron Configuration Exceptions yCopper EXPECT :[Ar] 4s 2 3d 9 ACTUALLY :[Ar] 4s 1 3d 10 yCopper gains stability with a full d-sublevel. D. Stability

14. zElectron Configuration Exceptions yChromium EXPECT :[Ar] 4s 2 3d 4 ACTUALLY :[Ar] 4s 1 3d 5 yChromium gains stability with a half-full d-sublevel. D. Stability

15. zIon Formation yAtoms gain or lose electrons to become more stable. yIsoelectronic with the Noble Gases.

16. O 2- 10e - [He] 2s 2 2p 6 D. Stability zIon Electron Configuration yWrite the e - config for the closest Noble Gas yEX: Oxygen ion O 2- Ne