Physics D

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Across
  1. 4. most penetrating for of radiation
  2. 6. when a substance has another mixed or disposed within it
  3. 7. number of counts from a sample per second
  4. 10. the time for the number of nuclei to reduce by half
  5. 12. centre of an atom
  6. 16. household appliance that uses radiation
  7. 17. the unit of which activity is measured in
  8. 18. the cause an atom to become charged by gaining or losing an electron
  9. 20. can penetrate paper but no aluminium
  10. 21. responsible for the nuclear model of the atom
  11. 22. group 0 elements
Down
  1. 1. sub-atomic particle with a positive charge
  2. 2. process of exposing an object to a source of radiation
  3. 3. the most ionising type of radiation
  4. 5. an element that is likely to react with another element
  5. 8. responsible for plum pudding model
  6. 9. sub-atomic particle with a negative charge
  7. 11. atoms of the same element with a different number of neutrons
  8. 13. what the electrons are on
  9. 14. sub atomic particle with no charge
  10. 15. alpha particle has what type of nucleus
  11. 19. the charge of an atom