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History of the Atom

From Atomism to the Nuclear Model

Jack F. Eichler
Department of Chemistry
University of California, Riverside


In this clicker case, students are guided through the history of atomic structure, and in the spirit of discovery learning, use data from historical experiments to discern the different models of the atom. In particular, students move from the time of Democritus in the 5th century BCE to the time of Moseley in the early 1900s as they learn how the nuclear model of the atom was developed. Students not only learn about the different models of the atom and how they evolved over time, and about the fundamental particles of matter, but they also engage in higher-order critical thinking. This is accomplished by having the students interpret the data from historical experiments (cathode ray tube, gold foil experiment, etc.) and decide which models of the atom are most appropriate as the interpretable evidence changes over time. This case is designed to be used in a first-semester/first-quarter general chemistry course, and is generally presented to the students in the first two weeks of the course.


  • Learn the fundamental particles that act as the building blocks of mater.
  • Learn about the historical experiments that provided the evidence used to develop the different models of the atom over time.
  • Learn about the pre-quantum model of the atom, and be able to work with concepts such as atomic number and atomic mass.
  • Be able to use data/evidence to arrive at a valid conclusion, in particular by using historical evidence to discover the various models of the atom that were developed over time.


Atomic structure; atomic particles; models of the atom; atomic mass; atomic number; Democritus; Dalton; Thompson; Rutherford; Moseley

Educational Level

High school, Undergraduate lower division


PDF, PowerPoint

Type Methods

Clicker, Interrupted, Lecture



Subject Headings

Chemistry (General) Science (General)

Date Posted


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Sharla Dowding
Science Department
Newcastle High School
Newcastle, WY
THANK YOU for posting this case! I hope lots of high school chemistry teachers download and use it as they teach atomic structure! Although I will not be able to use it all at one setting, it will greatly enhance my current unit. I love the questions!

Brigid Corrigan
Mount Sackville
I hope to use the history of the atom case study with my students in Ireland. The website of case studies is a great idea, thanks for making it available.