Q1: The decay of Osmium-186 by electron capture. A1:  Q2: The decay of Uranium-235 by positron emission. A2:  Q3: The decay of Radium-220 by beta emission. A3:  Q4: Bombardment of Bismuth-210 with a neutron produces Bismuth-211 and one other particle. A4:  Q5: The decay of Uranium-238 by alpha emission. A5:  Q6: The decay of Lead-214 by alpha emission. A6:  Q7: The decay of Bismuth-210 by beta emission. A7:  Q8: Bombardment of Nitrogen-14 with a proton produces Carbon-14 and one other particle. A8:  Q9: The decay of Polonium-210 by alpha emission. A9:   Short Answer 12. Why are larger nuclei such as Bismuth and upwards all radioactive? Larger nuclei are unstable and radioactive. 13. How do strong nuclear forces hold the nucleus together, and what subatomic particles are involved? Strong nuclear force; protons and neutrons. Multiple Choice 14. Which material(s) blocks gamma radiation? Lead. 15. Which material(s) blocks beta radiation? Aluminum. 16. Which material(s) blocks alpha radiation? Paper. 17. The sun is which type of bombardment reaction? Fusion.