Proton Neutron Rotation and Nuclear Stability
Initial Publication Date: August 25, 2009
Summary
In this physics activity, students will review and investigate stability of the nucleus of various elements. They will then determine factors that affect the stability of the nucleus. Students will determine N (number of neutrons) and Z numbers (number of protons) for the different elements. At this point you should review Coulomb Forces between the protons.
Now the idea that different nuclear parts have two types for spin should be introduced. Similar to the spin of the electrons in different orbitals, discuss up and down spins for both protons and neutrons. Then complete the tables on the worksheet putting pairs of neutrons with neutrons and pairs of protons with protons. (both showing up and down spin for each nucleon. ) Now you can change C-15 to N-15 and O-13 to N-13. This is performed for several elements which are unstable.
Then review transformation of the nucleus and how this happens through Neutron decay, Proton decay or Electron capture. Students will then determine how a nucleus becomes stable by one of these methods.
CollapseLearning Goals
Students should get a basic understand of why certain nuclei are unstable and what type of decay occurs that will make them more stable. Higher order thinking can be introduced showing other factors which affect the nucleus stability and are in the Semiempirical Binding Energy Formula: Eb (A,Z) = aI - aS A^2/3 - aC A^ -1/3 - aA (A-2Z)^2 / A^-1 where aI -Interior Bonding, aS - Surface correction, aC - Coulomb repulsion, aA - Asymmetry coefficients , Z – Number of Protons, and A - Total Mass. There are several terms which may be new to students and should be defined.
Context for Use
This lesson can be used with physics, chemistry or physical science classes when discussing radioactivity and nuclear decay. This is a class lesson activity used with lecture which can be completed in one class period and expanded upon if so desired. Students should have an understanding of nuclear particles, there location and that they are thought of as having some type of spin. The concept is very basic and can be used with any audience which has basic nuclear understanding.
Description and Teaching Materials
- Warm Up – Review Bohr's model of the nucleus. Have students determine the number of protons and neutrons in a nucleus. (Engage)
- Review note sheet and introduce the concept of protons and neutrons being paired with opposite spins. (relate to electrons) (Explore & Explain)
- Introduce the strong force (holding the nucleus together). Introduce and show factors affect binding energy of a nucleus. (Explore & Explain)
- Visualize the release of a nuclear particle by overcoming the binding energy. (Explore & Explain)
- Engage students in completing the different levels of protons and neutrons in a nucleus. (Extend)
- Explain three different types of Beta decay. What happens to the nucleus? New element formed. (Explain)
- Engage students in identifying the type of decay based on element mutation. (Extend)
- After review of types of decay, students are to complete a decay chain determining the type of decay based on type of particle emission starting with U-238 to Lead – 206.
- Review nuclear stability. Vocabulary: Why radioactive or non-radioactive? (Engage) Lesson Plan (Microsoft Word 2007 (.docx) 16kB Aug18 09) Guided worksheet for when lesson is given. (Microsoft Word 2007 (.docx) 25kB Aug18 09) Decay Chains and type of particle emission (Microsoft Word 2007 (.docx) 13kB Aug18 09) Semi-empirical Binding Energy Formula (Microsoft Word 2007 (.docx) 10kB Aug18 09)
- Review note sheet and introduce the concept of protons and neutrons being paired with opposite spins. (relate to electrons) (Explore & Explain)
- Introduce the strong force (holding the nucleus together). Introduce and show factors affect binding energy of a nucleus. (Explore & Explain)
- Visualize the release of a nuclear particle by overcoming the binding energy. (Explore & Explain)
- Engage students in completing the different levels of protons and neutrons in a nucleus. (Extend)
- Explain three different types of Beta decay. What happens to the nucleus? New element formed. (Explain)
- Engage students in identifying the type of decay based on element mutation. (Extend)
- After review of types of decay, students are to complete a decay chain determining the type of decay based on type of particle emission starting with U-238 to Lead – 206.
- Review nuclear stability. Vocabulary: Why radioactive or non-radioactive? (Engage) Lesson Plan (Microsoft Word 2007 (.docx) 16kB Aug18 09) Guided worksheet for when lesson is given. (Microsoft Word 2007 (.docx) 25kB Aug18 09) Decay Chains and type of particle emission (Microsoft Word 2007 (.docx) 13kB Aug18 09) Semi-empirical Binding Energy Formula (Microsoft Word 2007 (.docx) 10kB Aug18 09)
Teaching Notes and Tips
- Warm Up – Review Bohr's model of the nucleus. Have students determine the number of protons and neutrons in a nucleus. (Engage)
- Review note sheet and introduce the concept of protons and neutrons being paired with opposite spins. (relate to electrons) (Explore & Explain)
- Introduce the strong force (holding the nucleus together). Introduce and show factors affect binding energy of a nucleus. (Explore & Explain)
- Visualize the release of a nuclear particle by overcoming the binding energy. (Explore & Explain)
- Engage students in completing the different levels of protons and neutrons in a nucleus. (Extend)
- Explain three different types of Beta decay. What happens to the nucleus? New element formed. (Explain)
- Engage students in identifying the type of decay based on element mutation. (Extend)
- After review of types of decay, students are to complete a decay chain determining the type of decay based on type of particle emission starting with U-238 to Lead – 206.
- Review nuclear stability. Vocabulary: Why radioactive or non-radioactive? (Engage)
- Review note sheet and introduce the concept of protons and neutrons being paired with opposite spins. (relate to electrons) (Explore & Explain)
- Introduce the strong force (holding the nucleus together). Introduce and show factors affect binding energy of a nucleus. (Explore & Explain)
- Visualize the release of a nuclear particle by overcoming the binding energy. (Explore & Explain)
- Engage students in completing the different levels of protons and neutrons in a nucleus. (Extend)
- Explain three different types of Beta decay. What happens to the nucleus? New element formed. (Explain)
- Engage students in identifying the type of decay based on element mutation. (Extend)
- After review of types of decay, students are to complete a decay chain determining the type of decay based on type of particle emission starting with U-238 to Lead – 206.
- Review nuclear stability. Vocabulary: Why radioactive or non-radioactive? (Engage)
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Assessment
During the lesson – walk about the room an visually inspect the notes sheet to see that students are doing correctly. Make corrections as needed. Allow the students to complete different aspects of the notes worksheet to be corrected later. Give the homework sheet and have the students complete the first 3 problems. Verify that students have identified the proper decay for each nuclear change
Standards
Strand: 2. Physical Science
Sub-strand: 1. Matter
Standard: 1. The structure of the atom determines chemical properties of elements.
Code: 9.2.1.1.4
Benchmark: Explain that isotopes of an element have different numbers of neutrons and that some are unstable and emit particles and/or radiation.
Sub-strand: 1. Matter
Standard: 1. The structure of the atom determines chemical properties of elements.
Code: 9.2.1.1.4
Benchmark: Explain that isotopes of an element have different numbers of neutrons and that some are unstable and emit particles and/or radiation.