Name:_____________________________ Period: 1 2 3 4 5 6 7 Date:_________________ History of Atoms Reading Guide (Pages 81-90) 1. Greek philosophers believed that all matter is made of only four elements. What were those 4 elements? 2. Democritus was a Greek philosopher that came up with some of the first ideas about atoms. Summarize his ideas below in 2-3 complete sentences. 3. Who was John Dalton? What were his 4 main ideas that made up his atomic theory? 4. What is the definition for an atom? 5. How small are atoms? 6. Describe who J.J. Thomson was and what research he did to discover more about atoms. (Use at least 3 complete sentences to answer this question) 7. What is an electron? 8. What did Thompsons’s atomic model look like? 9. Describe who Ernest Rutherford was and what research he did to discover more about atoms. (Use at least 3 complete sentences to answer this question) 10. With regards to an atom what is a nucleus and a proton? Nucleus: Proton: 11. Who discovered that atoms have a neutron? What is a neutron? 12. What did Niels Bohr’s model of the atom look like? What did the electrons look like in this model? What are some limitations with this model? Bohr Model Appearance: Description of Electrons: Limitations with Model: 13. What is the new modern atomic model theory? How do electrons behave in this theory? 14. Why do you think ideas about atoms changed so much throughout history? (This is not directly in your book; it will require you to think about the progression of the atomic model) Answer this question using at least 3 complete sentences. 15. What are quarks?