2. CLICK HERE TO BEGIN! Directions: Click the term that correctly matches the definition in each question.

3. 1. Process in which an unstable atomic nucleus emits charged particles and energy. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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6. 2. Time required for one half of a sample of a radioisotope to decay. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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9. 3. Attractive force that binds protons and neutrons together in the nucleus. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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12. 4. Any atom containing an unstable nucleus. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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15. 5. Splitting of an atomic nucleus into two smaller parts. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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18. 6. Charged particles and energy that are emitted from the nuclei of radioisotopes. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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21. 7. A series of fission reactions triggered by neutrons released during the fission of a nucleus. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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24. 8. Positively charged particle made up of two protons and two neutrons. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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27. 9. Smallest possible mass of a fissionable material that can sustain a chain reaction. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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30. 10. An electron emitted by an unstable nucleus. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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33. 11. Penetrating ray of energy emitted by an unstable nucleus. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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36. 12. Nuclear radiation that occurs naturally in the environment. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation

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39. 13. Process in which the nuclei of two atoms combine to form a larger nucleus. Chain Reaction Radioactivity Critical Mass Strong Nuclear Force Radioisotope Half-life Fission Gamma Ray Nuclear Radiation Beta Particle Fusion Alpha Particle Background Radiation