The Nuclear Atom: Particles, Nucleus and Isotopes

Name: The Nuclear Atom: Particles, Nucleus and Isotopes
Author: StemPy Lab

How do you weigh something that no one has ever seen? Thomson, Millikan and Rutherford did it with glowing tubes, oil drops and a thin gold foil. In this course we see how the electron, the proton and the neutron were found, how big the nucleus is, and how a mass spectrometer finds the isotopes of an element.

3 lessons, about 1 h 25 min3 simulations10 problems6 practice questionsPython in every lesson

Created by StemPy Lab

Course outline (3 lessons)

Lesson 1about 30 min
Finding the electron, the proton and the neutron
Thomson found that cathode rays are a stream of negative particles, the electrons, and measured their charge to mass ratio. Millikan measured the charge, so the mass could be found. Goldstein found the proton, and Chadwick found the neutron.
1 simulation2 practice questions1 Python program4 problems
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Lesson 2about 30 min
Rutherford's nuclear atom and the size of the nucleus
Rutherford fired α particles at gold foil. Most went straight, a few were turned through large angles. So the positive charge and almost all the mass are in a tiny nucleus of radius $R = 1.2\ \text{fm} \times A^{1/3}$ , and the atom is mostly empty space.
1 simulation2 practice questions1 Python program3 problems1 Python lab
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Lesson 3about 25 min
Atomic number, mass number and isotopes
The atomic number Z is the number of protons and the mass number A is the number of protons plus neutrons. Isotopes have the same Z and different A, isobars have the same A, and isotones have the same number of neutrons. A mass spectrometer separates the isotopes by mass, and the atomic mass is their weighted average.
1 simulation2 practice questions1 Python program3 problems1 Python lab1 question set1 note
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Nuclear Atom: Practice Paper

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The Nuclear Atom: Particles, Nucleus and Isotopes

Course outline (3 lessons)

Finding the electron, the proton and the neutron

Rutherford's nuclear atom and the size of the nucleus

Atomic number, mass number and isotopes

Test Your Learning

Your teacher

Discussion (0)