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Drill 10/12 Who was your scientist from last class? Was his model of the atom what we accept today? Was it completely wrong? Slide 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. Slide 3 Drill 10/13 What is everything that is inside an atom? Slide 4 Thompsons Cathode Ray Tube Experiment Slide 5 Cathode Ray Tube Demonstration Slide 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. Slide 7 Magnets Magnets have a positive and a negative side. Positive is attracted to negative Negative is attracted to positive Slide 8 Cathode Rays + - Slide 9 + - Slide 10 + - Slide 11 + - Slide 12 Cathode Ray Tube Demonstration Slide 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! Slide 14 Called the plum pudding model Slide 15 Rutherfords Gold Foil Experiment Slide 16 Slide 17 Rutherfords 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. Slide 18 Rutherfords Conclusions In Rutherfords 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 Slide 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. Slide 20 Bohr Planetary Model of the atom Slide 21 Heisenberg & Schrdinger Their ideas together gave us the ELECTRON CLOUD model. This is our current atomic model. Slide 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. Slide 23 Antimatter i. What do you think antimatter is? ii.Where do you think antimatter came from? iii.Where is all the antimatter now?