Module 7
1. Module 7
1.2. In this Module
Module 7—Investigating the Nature of the Atom
In This Module
Lesson 1—Cathode Rays and Thompson’s Experiment
In this lesson you will learn about the discovery of the electron and its charge-to-mass ratio. You will explore early experiments with cathode ray tubes and the applications of such technologies in modern mass spectrometers.
You will investigate the following essential questions:
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How did the cathode ray contribute to the development of atomic models?
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How did J. J. Thomson determine the charge-to-mass ratio of an electron?
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How did Thomson’s experiment contribute to science and technology?
Lesson 2—The Millikan Experiment
In this lesson you will learn about Millikan’s oil drop experiment and how he determined the elementary charge of an electron using scientific judgment.
You will investigate the following essential questions:
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How were Millikan’s experimental design and apparatus applied to determine the charge of a single electron?
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How did the new fundamental quantity, the elementary charge, inform models of the atom?
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Why did Millikan’s use of scientific judgment cause a controversy among other scientists and scholars?
Lesson 3—The Rutherford and Bohr Models of the Atom
In this lesson you will explore information about the atom revealed by its interaction with electromagnetic radiation and with charged particles.
You will investigate the following essential questions:
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What does Rutherford’s scattering experiment suggest about the nature of the nucleus, and how did it lead to the planetary model of the atom?
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What is the Bohr model of the atom? How is the concept of stationary states and energy quantization used to explain how a gas absorbs and emits only certain wavelengths of electromagnetic radiation?