1. Honors Chemistry Chapter 3 Atomic Structure

2. I. Dalton’s Theory Part 1 - elements are composed of tiny particles called atoms. Part 2 - Atoms from the same element are identical. Part 3 - Atoms are neither created nor destroyed in a chemical reaction. (just a new order with new bonds) Part 4 - A given compound has the same relative numbers and kinds of atoms. *water is always H 2 O

3. II. Discovering Atomic Structure A.Faraday (1839) 1. -atoms contain particles that have electrical charges B.Franklin 1. Tests electricity And proved that…

4. III. The Electron A. Cathode Ray Tube JJ Thomson (1896) - Led to the discovery of the electron and its basic charge.

5. B.Millikan (1909) 1. Determined the charge and mass of a single electron. 2. 1 electron = 2000 times lighter than an H atom

6. IV. The Proton and Nucleus A.Gold Foil Experiment (Rutherford 1909) -determined nucleus (positive charge)

7. Assign: 3.1 Read 3.3 and draw a picture of Cl-35 and Cl- 37 with the correct number of protons, electrons, and neutrons.

8. V. Structure of the Atom Particle TypeChargeRelative Mass Electron (cloud)1-0 Proton (nucleus)1+1 Neutron (nucleus)01

9. VI. Terminology and the P.T. A.Atomic Number - # of protons in an atoms 1. top number 2. gives clue to the number of electrons B. Mass Number – the # of protons and neutrons 1. always rounded C. Ions – atom that has gained or lost electron(s) 1. Ex: Ca  20 Ca 2+  ___ 2. Can be positive or negative 18

11. ElementSymbolAtomic #Mass # # of electrons # of neutrons # of protons Carbon 13 65 Fe 3+ O 2- 1012 3218 86 C612666 Aluminum Al27 1314 13