Atomic structure

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Across
  1. 2. consisting of protons and neutrons and containing nearly all its mass.
  2. 5. positively charged particle of matter found in the atoms of all elements.
  3. 8. has a neutral charge
  4. 10. protons + neutrons
  5. 12. has 2 valence electrons but grouped with elements with 8
  6. 14. when an atom is most stable it has 8 valence electrons
  7. 15. A small particle with a negative charge
  8. 17. equal amount of electrons and protons
  9. 18. more protons than electrons
  10. 19. level closest to the nucleus
Down
  1. 1. 2 forms of the same element same protons
  2. 3. table where elements are put in a table
  3. 4. Number of protons
  4. 6. molecule with net charge
  5. 7. basic unit of a chemical element
  6. 9. electrons on the outer most level
  7. 11. 1 on the periodic table
  8. 13. chemical symbol representing the nucleus and all internal electrons
  9. 16. more electrons than protons