Atomic structure

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Across
  1. 3. An equation used to represent radioactive decay.
  2. 6. A treatment where radiation is used to kill cancer cells
  3. 9. A chemical compound containing a radioactive isotope that is used to see inside bodies by detecting radiation it emits.
  4. 10. The level of ionisation caused by each type of nuclear decay.
  5. 12. The centre of an atom, consisting of protons and neutrons. It is positively charged.
  6. 14. The time it takes for the number of nuclei of the isotope in a sample to halve, or the time it takes for the count rate (or activity) from a sample containing the isotope to fall to half its initial level.
  7. 16. The continuous spectrum of electromagnetic waves. From long to short wavelength the groups are: radio, microwave, infrared, visible light, ultraviolet, X-rays and gamma rays.
  8. 17. The process of exposing an object to ionising radiation.
  9. 18. he process of releasing or giving out.
Down
  1. 1. The splitting of a large and unstable nucleus to form two smaller nuclei. The nucleus emits two or three neutrons plus gamma rays. Energy is released by the reaction.
  2. 2. The extent to which a type of radiation can be transmitted through, rather than being absorbed, by a material.
  3. 4. The joining of two light nuclei to form a heavier nucleus. In this process some of the mass may be converted into the energy of radiation and released.
  4. 5. The process of receiving or taking in.
  5. 7. The distance from the nucleus of an atom where electrons orbit. Also called a shell.​
  6. 8. The radiation that is around us all of the time. It comes from: ·natural sources such as rocks and cosmic rays in space; ·humanly-constructed sources such as the fallout from nuclear weapons testing and nuclear accidents.
  7. 11. A self-sustaining chemical reaction in which one reaction causes further reactions, which in turn cause further reactions, and so on.
  8. 13. A measure of the risk of harm resulting from an exposure of the body to radiation, measured in sieverts (Sv).
  9. 15. The number of radioactive particles (𝜶, 𝜷 or 𝛄) recorded each second by a detector such as a Geiger-Muller tube.