1. TOPIC: 4.2 History of the Atom EQ: How has the model of the atom changed over time?

2. Left hand Draw an atom and label the parts if you them. 30 seconds go! We are going to go over the history of the atom and we are going to see how your picture measures up!

3. Democritus (460 – 370 BCE) “ Atoms are indivisible and indestructible”

4. How big is an atom? A penny contains 2.4 x 10 22 atoms of copper The world’s population is only ~ 6 x 10 9 people The radius of one atom is between 5 x 10 -11 m and 2 x 10 -10 m

5. The History of the ATOM -Dalton -Thomson -Rutherford -Bohr -Current Quantum Model

6. Dalton Thomson Rutherford Bohr Quantum Model Graphic organizer for history of an atom

7. John Dalton (1766 – 1844) Studied gases and started to figure out that various elements had different masses.

8. DALTON concluded… All elements are composed of tiny indivisible particles called atoms. DALTON’S Model

9. THEN THOMSON CAME ALONG…

10. J J Thomson (1856 – 1940) Cathode Ray Tube 4.2

11. Different metals, same charge and mass of particles

12. Thomson concluded... Electrons (e - ) are tiny, negatively charged particles Thomson’s Plum Pudding Model

13. THEN RUTHERFORD CAME ALONG…

14. Ernest Rutherford (1911) Rutherford’s Gold-Foil Experiment 4.2

15. The Atomic Nucleus Atoms have dense centers (protons and neutrons) with lots of space around them (electrons). 4.2

16. Rutherford Concluded… small positively charged nucleus, containing much of the atom's mass Rutherford model

17. nucleus atom

18. THEN BOHR CAME ALONG… He used the laws of physics to explain why the positive nucleus and the negative electrons stayed apart. He worked specifically with Hydrogen.

19. Niels Bohr concluded (1913)… electrons move in a set path called an orbit Bohr Model

20. THEN Erwin Schrodinger came along… He found a mathematical model that worked for all atoms…not just Hydrogen Modern Model of the Atom (just watch through :59) http://www.youtube.com/watch?v=5FHSj8Iwz4U

21. Erwin Schrodinger’s concluded (1926)… Electrons are found in electron clouds Quantized Model

22. The propeller blade has the same probability of being anywhere in the blurry region, but you cannot tell its location at any instant. The electron cloud of an atom can be compared to a spinning airplane propeller.

23. Erwin Schrodinger’s model (1926) Quantum mechanical model—describe possible energy and probable location of electron

25. On the left hand page across from design a t-shirt that shows the progression of the model of the atom.

27. v v

29. For Integrated Science we will use this model

30. For Chemistry you will use this model

31. Left hand Draw an atom and label the parts if you them. 30 seconds go! We are going to go over the history of the atom and we are going to see how your picture measures up! Remember this slide? Compare with your partner..how does your atom look?

32. Summary