Physical Science Module 13 Vocabulary

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Across
  1. 4. Largest subatomic particle with no charge; resides in the nucleus of an atom
  2. 7. When an unstable nucleus emits two protons and two neutrons (actually a helium nucleus)
  3. 10. The high energy photon that is emitted in gamma decay
  4. 11. A schematic description of a system that accounts for its known properties
  5. 12. The paricle that is exchanged in the nucleus between protons and neutrons, resulting in the strong nuclear force
  6. 13. The sum of the numbers of neutrons and protons in the nucleus of an atom
  7. 14. When the fact that radioactive isotopes decay at a measurable rate is used as a means of dating objects of unknown ages
  8. 16. A chart that organizes atoms by grouping them in terms of how many protons they have
  9. 17. Bohr Scientist who proposed a model for the atom that has protons and neutrons in the nucleus with electrons orbiting like planets
  10. 18. When an unstable nucleus emits a high energy photon
  11. 20. positively charged subatomic particle that resides in the nucleus of an atom; 2000x
  12. 21. When an unstable nucleus changes a neutron into a proton and emits an electron in the process
Down
  1. 1. Atoms with the same number of protons but different numbers of neutrons
  2. 2. An atom with a nucleus that is not stable
  3. 3. The current, very complex, model of the atom which relies heavily on higher math
  4. 5. The time it takes for half of the original sample of a radioactive isotope to decay
  5. 6. than electrons, but slightly smaller than neutrons
  6. 8. The process by which an unstable atom decays in order to become stable
  7. 9. The number of protons in an atom
  8. 15. Negatively charged subatomic particle that resides far outside the nucleus of an atom; smallest of the three particles
  9. 19. The center of an atom, containing the protons and neutrons