1. To Do… Electronic homework (Lon-Capa) HW6 Type 1 due Monday, April 21 by 7 pm; HW6 Type 2 due Wednesday, April 23 by 7 pm Friday: Text homework. Lab write-up. Discuss exam Tuesday’s lecture: Chapter 11 1

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5. Overall goal: Atomic StructureChemical Bonding3D Molecular StructureMolecular Properties 5

6. Big Ideas – Periodic Table Originally arranged by atomic mass (protons not discovered). See Co & Ni; Te & I. Separated as “metals” and “nonmetals” (appearance/properties) Chemical reactivity 6

7. Big Ideas – Periodic Table The closer together the elements on the periodic table, the more chemically alike they are. Especially true for elements in the same column. “Missing” elements were predicted. 7

8. Big Ideas – Models Models are not reality. We use different models for different reasons. A model should be as simple as possible, but not simpler (Einstein) To answer more questions, the model must be more complex. 8

9. Various Atomic Models (Ch. 4) Dalton: Indivisible atoms J.J. Thomson: Atoms emit tiny negative particles. (Therefore atoms not indivisible!) William Thomson (Lord Kelvin): formulates the Plum Pudding Model. Rutherford: Some α -particles bounce back when shot at atoms. (There is a concentration of mass with a positive charge in the atom.) http://www.youtube.com/watch?v=5pZj0u_XMbc 9

10. Figure 11-1 p239