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Student Exploration: Isotopes

Vocabulary:atomic number, band of stability, half-life, isotope, isotope notation, mass number, radioactive, radioisotope

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

What particles make up an atom?

Which of these are found in the nucleus?

Which particles are charged?

Gizmo Warm-up

You may think that all atoms of an element are the same, but that is not the case. Atoms of an element can come in several different versions. Some of these versions are stable, while others can break down. In the Isotopes Gizmo, you will explore different versions of the elements.

To begin, check that Hydrogen-1 is selected. Check that Show isotope notation is selected.

Click the up and down arrows for protons and neutrons and notice what changes.

Which particle determines the element?

Which particle creates a different version of the same element?

Atoms of the same element with different numbers of neutrons are called isotopes.

Set protons and neutrons to 6.

Which isotope was created?

What percentage of the element consists of this isotope?

Add a neutron. Which isotope do you have now?

What percentage of the element consists of this isotope?

Activity A:

Isotope notation

Set protons to 2 and neutrons to 2.
Check that Show isotope notation is selected.

Question: How are isotopes written down?

Explore: Below the helium atom you see the isotope notation for helium-4.Add and subtract protons and neutrons a few times using the arrow buttons. Notice how the isotope notation changes when you do this.

What does the top number equal?

Which particle determines the atomic number?

In isotope notation there are two numbers to the left of the element symbol. The top number is the mass number (A). The mass number is the sum of the protons and neutrons. The bottom number is the atomic number (Z). The atomic number is the number of protons.

Apply: Turn off Show isotope notation. Set protons to 3 and neutrons to 4.

Write this isotope using isotope notation. Check your answer in the Gizmo.

Observe: Set the protons to 8 and the neutrons to 9.

How is the isotope written at the top left of the gray box?

What does the number next to the element name indicate?

Practice: Turn off Show isotope notation. Use what you have learned to fill in the table. When you are finished, check your answers in the Gizmo.

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