Radioactivity

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Across
  1. 5. force that holds the nucleus together
  2. 6. when neutron decays into proton and releases an electron
  3. 8. become converted to ions
  4. 11. maintaining equilibrium
  5. 12. device used to detect radiation
  6. 14. splitting a large atom into 2 smaller atoms
  7. 15. force that electric charges exert on each other
  8. 17. particle made of 2 protons and 2 neutrons (emitted during decay)
  9. 20. decaying from one element into another
Down
  1. 1. amount of time needed for 50% of a radioactive substance to decay
  2. 2. positively charged dense center of atoms
  3. 3. direct high energy particles or radiation against on atom
  4. 4. force of attraction between 2 objects
  5. 7. newly created atom (after radioactive decay)
  6. 9. combining 2 small atoms to make a larger atom
  7. 10. original element (before radioactive decay)
  8. 13. when unstable nucleus decays and emits particles
  9. 16. atoms of the same element with different number of neutrons
  10. 18. give off, send forth, discharge
  11. 19. radiation of energy without particles