1. Dalton’s Atomic Theory

2. Each element is made up of atoms The atoms of a given element are identical Chemical compounds are formed when atoms of different elements combine with each other Chemical reactions involve reorganization of the atoms, and changes the way they are bound together. Atoms not changed.

3. Periodic Table Dalton made the first PT using atomic masses of elements Gay-Lussac and Avogadro also contributed to the early research on atoms

4. Characteristics of Atoms The Electron Thomson-cathode ray tube Identified negatively charges particles called electrons Charge of -1.76 x 10^8 C/g Thought that atom was a “plum pudding” with a diffuse cloud containing “raisin” electons

5. Rutherford Disproved “plum pudding” model Came up with Nuclear Atom (diffuse cloud of electrons orbiting a large,, positively-charged nucleus)

6. Atomic Structure Electron, small mass, negative charge, orbit Proton, large mass, positive charge, nucleus Neutron, large mass, no charge, nucleus P. 50

7. Atomic Number # Electrons # Protons Location of PT

8. Atomic Mass Number Mass of atom in amu # protons and neutrons combined

9. Look at board and PT for examples of atomic mass and number Must know first 50 elements on PT plus others Know how to calculate electrons, protons and neutrons

10. Homework Flashcards—on your own Worksheet