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Thomson and Rutherford’s contributions to the model of the atom

Thomson and Rutherford’s contributions to the model of the atom. J.J. Thomson’s Atomic Model. Thomson discovered the electron while experimenting with cathode rays. -. Electrons have a negative charge. Thomson believed:

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Thomson and Rutherford’s contributions to the model of the atom

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  1. Thomson and Rutherford’s contributions to the model of the atom

  2. J.J. Thomson’s Atomic Model Thomson discovered the electron while experimenting with cathode rays. - Electrons have a negative charge • Thomson believed: • The atom was a positive sphere with electrons embedded in it like raisins in a plum pudding. It looks like a chocolate chip cookie!!!

  3. Cathode Rays A cathode ray tube is a sealed evacuated glass tube. Cathode rays are beams of tiny, negatively charged particles called electronsthat flow through this tube. J.J Thompson used these tubes to discover the various properties of cathode rays (electrons)

  4. Properties Of Cathode Rays 1. The cathode rays travel in a straight line. 2. The cathode rays drive a small propeller located in their path. This tells us that cathode rays have mass.

  5. continued... Properties Of Cathode Rays 3.The cathode rays cause the shadow of the object in their path to be projected on a fluorescent screen.

  6. continued... Properties Of Cathode Rays 4. The cathode rays are attracted towards the positively charged plate. This tells us that cathode rays are negative.

  7. EX# 1 Which of the following properties about cathode rays tell us that they are in fact negative? The cathode rays are deflected towards the positively charged plate. EX# 2 Which of the following properties about cathode rays tell us that they have mass? The cathode rays drive a small propeller located in their path.

  8. EX# 3 Draw Thomson’s atomic model. - - - - - - - - - Positive sphere with electrons embedded in it EX# 4 What did J.J Thomson use to find the properties of electrons The cathode ray tube and cathode rays

  9. RUTHERFORD’S ATOMIC MODEL Ernest Rutherford also developed his own atomic theory HE BELIEVED: the atom had a central positive nucleus surrounded by negative electrons floating around in a cloud like structure

  10. EX# 5 Which diagram is Thompson’s and which diagram is Rutherford’s? _ _ _ _ + _ Rutherford + _ + + _ _ + _ + _ + _ _ Thomson EX# 6 Rutherford believed the nucleus was POSITIVE or NEGATIVE?

  11. Key Points to Remember • Thomson’s Model is known as the plum pudding model. He also discovered the electron. • Memorize the four properties of cathode rays • Rutherford’s Model • Positive nucleus surrounded by a fuzzy cloud • Electrons not organized

  12. Activities • Worksheet # 6

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