Atomic Theory Dalton Thompson Rutherford Chadwick Bohr, Exercises of Chemistry

Download Atomic Theory Dalton Thompson Rutherford Chadwick Bohr and more Exercises Chemistry in PDF only on Docsity! CH.3 (PART IB) - History of the Atom Worksheet John Dalton (1766 -1844): John Dalton was an English chemist. His ideas form the atomic theory of matter. Here are his ideas. All elements are composed (made up) of atoms. It is impossible to divide or destroy an atom. All atoms of the same elements are alike. (One atom of oxygen is like another atom of oxygen.) eAtoms of different elements are different. (An atom of oxygen is different from an atom of hydrogen.) «Atoms of different elements combine to form a compound. These atoms have to be in definite whole number ratios. For example, water is a compound made up of 2 atoms of hydrogen and 1 atom of oxygen (a ratio of 2:1). Three atoms of hydrogen and 2 atoms of oxygen cannot combine to make water. 1. What is the name of John Dalton’s theory? 2. What are elements made of? 3. An atom of hydrogen and an atom of carbon are 4. What are compounds made of? 5. The ratio of atoms in HCL is: a) 1:3 b) 2:1 c) 1:1 J. J. Thompson (Late 1800s): J. Thompson was an English scientist. He discovered the electron when he was experimenting with gas discharge tubes. He noticed a movement in a tube. He called the movement cathode rays. The rays moved from the negative end of the tube to the positive end. He realized that the rays were made of negatively charged particles — electrons. 1. What did J.J. Thompson discover? 2. What is the charge of an electron? 3. What are cathode rays made of? 4. Why do electrons move from the negative end of the tube to the positive end? 5. What was Thompson working with when he discovered the cathode rays?