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

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Presentation transcript:

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: The atom was a positive sphere with electrons embedded in it like raisins in a plum pudding. It looks like a chocolate chip cookie!!!

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

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.

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

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

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

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

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

+ + _ _ _ _ _ _ _ _ _ _ _ _ Which diagram is Thompson’s and which diagram is Rutherford’s? Rutherford believed the nucleus was POSITIVE or NEGATIVE?

 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

Activities  Worksheet # 6