“Problems are not stop signs, they are guidelines.” Do Now Before the bell rings After the bell Pick up today’s handouts Get your interactive notebook In your seat Place your Half-Life homework on your desk with your name on it Respond to the following: “Problems are not stop signs, they are guidelines.” -Robert Schuller Still needs Do Now

Agenda  Do Now (5 min) Upcoming: Unit 2 Test Warm Up (5 min) Notes: Fission, fusion, decay (20 min) Javelin Throw (40 min) Independent Practice (15 min) Exit Slip (5 min) Closeout (2 min) Agenda

Nuclear Chemistry: Fission, fusion & decay Objectives: Describe the four fundamental forces of the atom. Compare and contrast nuclear fission and fusion. Distinguish between alpha, beta and gamma particles.

Guiding Question Should we continue to study nuclear energy?

Warm –Up: How? What? C – Level 1-2, amongst group H – Raise hand A – Discuss prompt M – None P –Recording responses on left page, discussing with group How much of a 500g sample of potassium-42 is left after 62 hours if the half-life of potassium-42 is 12.4 hours? How many Half-lives have gone by? H-L Time Amount 0 0 500 1 12.4 250 2 24.8 125 3 37.2 62.5 4 49.6 31.25 5 62 15.625

4 Fundamental Forces of Nature Gravity: Weakest, very long range for masses much larger than 2 individual atoms Electromagnetic: Very long range, helps structure of atoms and molecules, helps motion of electrically charged particles, helps with light’s interaction with matter Strong Force: Short range, very powerful, hold nucleus together Weak Force: Short range, responsible for nuclear decay

Types of nuclear reactions Fission Fusion Large elements break down into smaller elements to release energy Smaller elements combine into larger elements to release energy Think of a fissure Think of fusing things together

Nuclear Fission Advantages Disadvantages Used for nuclear bombs Can cause radiation Reactor accidents are dangerous (Meltdowns) Limited fuel supply (Uranium and Plutonium) Clean alternative energy source Creates lots of energy Used for nuclear bombs Just discuss this slide

Nuclear Fusion Advantages Disadvantages Creates even more energy Lots of fuel supply (Hydrogen) No radiation No risk of reactor accidents Used for Hydrogen bombs (8x more powerful than atomic bombs) Technology for clean energy hasn’t been developed yet It will require money and research Just Discuss this slide

SO, What exactly is radiation? Radioactivity refers to the particles which are emitted from nuclei as a result of nuclear instability. Because the nucleus experiences the intense conflict between the two strongest forces in nature, it should not be surprising that there are many nuclear isotopes which are unstable and emit some kind of radiation. SO, What exactly is radiation? Question: What are the two strongest forces in nature?

Radioactive decay Types of Radioactive Decay Alpha decay: Produces an alpha particle as a result Beta Decay: Produces a beta particle as a result Gamma Decay: Produces a gamma particle as a result Radioactive decay There is also positron decay Parent Isotope (Unstable) Daughter Product (Stable) α, β, or γ particle

There is also a positron emission  But we won’t discuss it

Side note: your TV produces beta particles… Discuss how alpha particles can be stopped by paper, whereas beta particles need a bit more to be stopped and gamma particles pretty much go through everything except lead or a few feet of concrete.

How to solve decay problems Express the isotope as a symbol (if necessary) Set up the equation Identify the total mass of each individual side The difference in masses will be the mass of the missing element. Complete steps 3 and 4 for the total protons Identify the missing element

What is the daughter product for the alpha decay of Plutonium-240? Express the isotope as a symbol Plutonium-240 Atomic mass = 240 Atomic number = 94 Atomic mass ? Pu 240 94 Atomic number

What is the daughter product for the alpha decay of Plutonium-240? 2. Set up the equation 240 94 Pu 4 2 He + ?

What is the daughter product for the alpha decay of Plutonium-240? 3. Identify the total mass of each individual side Mass: 240 240 94 Pu 4 2 He + ? Mass: 4

What is the daughter product for the alpha decay of Plutonium-240? 4. The difference in masses will be the mass of the missing element Mass: 240 Mass:4 240-4 = 240 94 Pu 4 2 He + 236 ? 236

What is the daughter product for the alpha decay of Plutonium-240? 5. Complete the same steps for number of Protons Protons: 94 94-2 = 240 94 Pu 4 2 He + 236 ? 92 Protons: 2 92

? U What is the daughter product for the alpha decay of Plutonium-240? 6. Identify the missing element Atomic mass = 236 Atomic number = 92 Atomic mass 236 92 U ? Atomic number

Now you try one e Li 6 3 -1 + ?

Activity: Javelin Throw How? What? C – Level 1-2, on-task discussion H – Raise hand A – Answering questions as a small group M – None P – Recoding answers on worksheet, head up, reading and thinking through all questions, discussing with group 30 minutes in small groups Use your notes and partner(s) to answer all questions

Exit Slip How? What? (5 min) C – No talking H – Raise hand A – Taking exit slip M – In seat P – Completing exit slip without notes and turning in If you finish early, summarize what you learned at the bottom of your notes OR answer today’s guiding question

Forgetting to stretch is a bear. Closing What are 3 key takeaways from today and yesterday? Complete the 3 Stretch questions Review for your test next class

Exit Slip Answers 1. 2. 3. 4.

Extra Practice problems if needed 1. 2. 3. 4. 5.

Answers! 1. 2. 3. 4. 5.

Extra Practice Problems if needed 1. 2. 3. 4. 5.

Answers! 1. 2. 3. 4. 5.