Parts of the Atom and Isotope Symbol

In 1918, Ernest Rutherford discovered the proton. Shortly after his discovery that atoms have a nucleus, Sir James Chadwick discovered the neutron in 1932. Until this time, Dalton’s theory about atoms was the accepted atomic theory. Dalton’s theory stated that atoms of the same element are identical, but the discovery of the neutron changed this theory. The number of neutrons within the nucleus of an atom can differ, creating isotopes. Before you learn more about isotopes, you will need to further investigate subatomic particles and the periodic table.

Atomic Structure

Atoms are composed of even smaller particles called protons, neutrons, and electrons. Each of these particles plays an important role in atomic structure. In this activity, use the arrows in the lower right corner to learn about each of these particles.

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The Periodic Table of Elements

The periodic table holds a lot of information that is important to chemists. In addition to providing a standardized record of all of the known elements, it also displays period trends. View this presentation to learn more about the periodic table and the information that it provides.

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Isotopes

Isotopes are like twins for an element. Isotopes have the same number of protons, but a different number of neutrons. Since the number of protons remains the same, the element keeps its identity. View this presentation to learn more about atoms, isotopes, and the periodic table.

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Atoms, Isotopes, and the Periodic Table Review

Review your knowledge of atoms, isotopes, and the periodic table of elements in this non-graded activity. Read each question and use the image provided to enter the correct answer in the blank space. Then, click SUBMIT to check your response. Click the interactivity thumbnail, and then click NEXT to get started.