1. Drill – 10/12 Who was your scientist from last class? Was his model of the atom what we accept today? Was it completely wrong?

2. To Conclude What is our current model of the atom called? Are the previous models completely wrong? Next class is PSATs. Thursday we will review scientists and go into atomic conversions.

3. Drill – 10/13 What is everything that is inside an atom?

4. Thompson’s Cathode Ray Tube Experiment

5. Cathode Ray Tube Demonstration

6. Cathode Ray Tubes Cathode rays are beams of current. They are emitted from a negative terminal, called a cathode, and travel to the positive terminal, called the anode.

7. Magnets Magnets have a positive and a negative side. Positive is attracted to negative Negative is attracted to positive

8. Cathode Rays + -

9. + -

10. + -

11. + -

12. Cathode Ray Tube Demonstration

13. Conclusions from the Cathode Ray Tube From these experiments, J.J. Thompson concluded that cathode rays are made up of negatively charged particles. It did not matter what element was put into the cathode ray tube, they all had negative particles that behaved the same way. These negative particles that all atoms have are called ELECTRONS!

14. Called the plum pudding model

15. Rutherford’s Gold Foil Experiment

17. Rutherford’s Experiment An experiment by Ernest Rutherford in 1911. He bombarded gold atoms with positively charged particles called alpha particles. Rutherford knew when the positively charged particles hit something because instead of passing straight through the gold foil they would bounce back or be deflected.

18. Rutherford’s Conclusions In Rutherford’s experiment, it seemed that he was required to send an incredible number of missiles to get a “hit.” He concluded that the grid of the atom must be composed of tiny, tiny cells and only one cell contains all of the positive charge of the atom

19. The atom is made up of mostly empty space with a small positively charged nucleus in the center. We now know that protons and neutrons make up the nucleus.

20. Bohr Planetary Model of the atom

21. Heisenberg & Schrödinger Their ideas together gave us the ELECTRON CLOUD model. This is our current atomic model.

22. Quarks – make up protons and neutrons. 6 types of quarks differ in mass and charge – up, down, strange, charmed, bottom, top. Leptons – make up electrons Gluons – hold quarks together (like glue!) Mesons – composed of one quark and one antiquark. Responsible for the forces in the nucleus.

23. Antimatter i. What do you think antimatter is? ii.Where do you think antimatter came from? iii.Where is all the antimatter now?