Radioactivity

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Across
  1. 2. A positively charged particle made of two protons and two neutrons.
  2. 3. Occurring unpredictably, with no fixed pattern or timing.
  3. 5. Unwanted radioactive material on or inside an object or body.
  4. 7. A random and spontaneous nuclear transformation releasing radiation.
  5. 10. Radiation that is always present in the environment.
  6. 13. A specific type of nucleus defined by its numbers of protons and neutrons.
  7. 15. Having unstable nuclei that emit radiation to become more stable.
  8. 17. A neutral particle found in the nucleus of an atom.
  9. 18. A positively charged particle found in the nucleus of an atom.
Down
  1. 1. Happening without any external cause or trigger.
  2. 4. The change of an unstable nucleus into a more stable one.
  3. 6. The number of nuclear decays per second of a radioactive source.
  4. 8. The process of forming charged particles by gaining or losing electrons.
  5. 9. The dense central part of an atom containing protons and neutrons.
  6. 11. High-energy electromagnetic radiation emitted from the nucleus.
  7. 12. A fast-moving electron emitted from an unstable nucleus.
  8. 14. Energy or particles emitted from a radioactive source.
  9. 16. Atoms of the same element with different numbers of neutrons.