Nuclear Decay and Transmutation Reactions Nuclear Unit Syllabus

Nuclear Decay and Transmutation Reactions

Nuclear Unit Syllabus • What is a rubric? – The rubric contains the expectations for the end product – what areas will be included and a scoring range for each area Rubric for Pros/Cons of Nuclear Power Presentation Needs Improvement Minimal Expectation Exceeds Expectations Time Less than 5 min Less than 10 min At 10 min Research No outside research 1 additional source 2 additional sources Material No equations Equations from lecture and outside sources Pros/Cons Polarized opinions only Pros/Cons but not balanced Balanced with final viewpoint and one additional question.

Nuclear Unit Syllabus • What is a rubric? – The rubric contains the expectations for the end product – what areas will be included and a scoring range for each area Rubric for Team Debates Needs Improvement Minimal Expectation Exceeds Expectations Polarized opinions/arguments only Good arguments but Good balanced not able to counter arguments with well other team thought out counter to other team Time Research Material Debate/ Counter

GLE • Describe Nuclear Stability and Decay • Describe Transmutation Reactions Objective • Student will compare stable nuclei at varying atomic mass numbers and discuss how unstable nuclei could reach the stable configuration, name the different types of particles involved, and discuss naturally occurring transmutations and transmutations of the transuranium elements.

Stability vs. Decay Activity • 3 X 5 Cards • Discuss why you think the configurations listed as stable are stable. • Discuss why the configuration listed as unstable is unstable • What would you do to get the unstable configuration to the stable configuration?

Stability vs. Decay • The stable nuclei on a neutron-versus-proton plot are located in a region called the band of stability. Unstable nuclei undergo spontaneous radioactive decay. The type of decay that occurs depends on the neutron-to -proton ratio of the unstable nucleus.

Stability and Decay

Types of Decay • Some nuclei have too many neutrons relative to the number of protons. These decay by turning a proton into a neutron and emitting a beta (electron) from the nucleus.

Types of Decay • Other nuclei are unstable because they have too few neutrons. These nuclei increase their stability by converting a proton to a neutron.

Types of Decay • A positron is a particle with the mass of an electron but a positive change. Its symbol is +1 e 0. A positron may be emitted as a proton changes to a neutron.

Types of Decay • All nuclei with atomic number greater than 83 are radioactive. They have both too many neutrons and protons to be stable. Most of them emit alpha particles.

Transmutation Reactions • Naturally occurring • Have already talked about several • Radioactive Decay • Another is the production of N -14 from naturally occurring C -14 (half life of 5715 years)

Transmutation Reactions • Earliest artificial transmutation was performed in 1919 by Ernest Rutherford by bombarding nitrogen gas with alpha particles.

Transmutation Reactions • Elements with Atomic Number above 92, the transuranium elements, all undergo transmutations. None of them occurs in nature. These elements have been synthesized in nuclear reactors and accelerators.

Homework • 1. – Page 856, #’s 12 and 13. • 3. – Page 851, #8 • Write out the text example for he synthesis of the transuranium element Plutonium by transmutation. • Explain the process of transmutation; write one nuclear equation to illustrate your answer.