Learning Goals ● Distinguish between stable and unstable nuclei ● Determine how the type of nuclear decay affects the number of protons and neutrons, mass number, charge, and isotope present ● Construct balanced nuclear equations to represent the different types of radioactive decay Open Play 1. Take 5 min to play with the Decay Screen of the PhET sim, Build a Nucleus . Describe three main things you have discovered: ● ● ● Then share your discoveries with a partner. ​ What is one discovery your partner made that you find interesting? Collect and Interpret Data Answer the following questions with your partner as you continue to explore the sim. 2. Create 3 isotopes of the same element – one stable and two unstable. How do they differ? Isotope symbol Proton amount Neutron amount Does it decay? Stable: Unstable: Unstable: Summarize the differences with your partner. Now examine the tables of 2 other groups. Does your summary correctly describe their results? If not, what changes or additions should you make? Isotopes with unstable nuclei are radioactive. Radioactive substances will spontaneously decay (break down) emitting a particle, energy, or both. 3. Create an isotope of platinum (atomic #78) that undergoes alpha (α) decay. a. What changes occur to the isotope as it decays? Before Decay After Decay symbol proton amount neutron amount mass charge (atomic number) Summarize these changes with your partner. b. What is the mass number and charge of an alpha particle? What is an alpha particle made up of? c. Construct a nuclear equation to represent the α decay of the platinum isotope you created. →