Atomic Theories and Models

Answer these questions on your own.

Early Ideas About Atoms: Go to http://www.infoplease.com/ipa/A0905226.html and read the section on “Greek Origins” in order to answer the following: 1. What were Leucippus and Democritus ideas regarding matter? 2. Describe what these philosophers thought the atom looked like? 3. How were the ideas of these two men received by Aristotle, and what was the result on the progress of atomic theory for the next couple thousand years?

Alchemists: Go to http://dictionary.reference.com/browse/alchemy and/or https://en.wikipedia.org/wiki/Alchemy to answer the following: 4. What was the ultimate goal of an alchemist? 5. What is the word used to describe changing something of little value into something of higher value? 6. Did any alchemist achieve this goal?

John Dalton’s Atomic Theory: Go to http://antoine.frostburg.edu/chem/senese/101/atoms/dalton.shtml and http://chemwiki.ucdavis.edu/Physical_Chemistry/Atomic_Theory/Postulates_of_Dalton%27s_atomic_th eory to answer the following:

7. When did Dalton form his atomic theory. 8. List the five/six ideas of Dalton’s theory: a. b. c. d. e.

Mendeleev: Go to http://www.chemistry.co.nz/mendeleev.htm and/or http://www.aip.org/history/curie/periodic.htm to answer the following: 9. What was Mendeleev’s famous contribution to chemistry? 10. How did Mendeleev arrange his periodic table? 11. Why did Mendeleev leave blank spaces in his periodic table?

J. J. Thomson: Go to http://www.universetoday.com/38326/plum-pudding-model/ and http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/atomic-and- nuclear-structure/thomson.aspx and http://www.chem.uiuc.edu/clcwebsite/cathode.html and http://www-outreach.phy.cam.ac.uk/camphy/electron/electron_index.htm and http://www.iun.edu/~cpanhd/C101webnotes/modern-atomic-theory/rutherford-model.html to answer the following: 12. What did JJ Thomson discover? 13. What is the year in which JJ Thomson made this discovery? 14. What was the evidence for “bodies much smaller than atoms”? 15. What model did JJ Thomson propose for the atom in 1904 (Hint: it refers to a type of food)?

Curie and Becquerel: Go to http://www.physics.isu.edu/radinf/cuire.htm http://www.chemheritage.org/discover/online-resources/chemistry-in-history/themes/atomic-and- nuclear-structure/curie.aspx and http://edtech2.boisestate.edu/lindabennett1/502/Nuclear%20Chemistry/types%20of%20decay.html to answer the following: 16. For what accomplishments did Marie Curie receive two Nobel prizes? 17. Who else received the first Nobel prize with Marie? 18. What are the three types of radioactive decay?

Ernest Rutherford and Neils Bohr: Go to http://www.pbs.org/wgbh/aso/databank/entries/dp13at.html and http://micro.magnet.fsu.edu/electromag/java/rutherford/ and http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/ruther14.swf to answer the following: 19. Go to the micro.magnet.fsu site. What do you observe when the slit width is adjusted to 4.0 nm? 20. How did Rutherford’s experiment disprove Thomson’s model of the atom? 21. What new model did Rutherford propose? Sketch it. 22. How much smaller was the nucleus, than the atom itself, according to Rutherford? 23. How did Bohr modify this model of the atom (what was his revolutionary idea about electrons?)

Millikan: Go to http://g.web.umkc.edu/gounevt/Animations/Animations211/MillikanOilDropExp.swf and http://www.montereymotiongraphics.com/example1.swf and http://www.webassign.net/resources/serpse8/activeFigures/25.22.swf After visiting the four sites, go back to the last link (webassign.net) to complete the following: 24. Press the bulb of the atomizer and observe. Describe what happens to the oil drops. 25. Now turn on the circuit by pressing the button on the bottom right so that it goes from reading OFF to reading ON. Spray the atomizer again. Describe the behavior of the drops. 26. Now play with the voltage by changing the potential difference. Spray the atomizer and observe. Move the voltage up and down and observe the drops. Record the voltage that makes some of the drops stay suspended in the middle of the apparatus. 27. Based on the interaction between the oil drops and the electric field, what did Millikan conclude?

Chadwick: Go to http://jameschadwickatomictheory.weebly.com/ and/or http://www.pbs.org/wgbh/aso/databank/entries/dp32ne.html to answer the following: 28. What observation led Chadwick (and Rutherford) to conclude there must be something besides just the proton in the nucleus of atoms? 29. What did Chadwick prove the existence of (what is the something besides just the proton called)? Compare its mass to that of a proton. 30. What makes up the atomic number? 31. What makes up the atomic mass (weight)?

Click the following link: http://www.chemtutor.com/struct.htm or http://www.ndt- ed.org/EducationResources/HighSchool/Radiography/subatomicparticles.htm or http://www.dummies.com/how-to/content/subatomic-particles-so-thats-whats-in-an-atom.html

32. The 3 subatomic 33. Location of the 34. Electrical charge particles subatomic particles within the atom