Chemistry Puzzle

1234567891011121314151617181920
Across
  1. 2. number The sum of the protons and neutrons in the nucleus of an atom.
  2. 6. number This number identifies the element and is equal to the number of protons
  3. 8. Weight The weighted average mass of all of an element's isotopes' mass numbers.
  4. 9. Process used to test a Hypothesis.
  5. 10. Positively charged subatomic particle found in the nucleus.
  6. 12. Having nonuniform composition throughout.
  7. 14. Factor that changes in an experiment.
  8. 16. A substance that contains only one kind of atom.
  9. 18. Cloud A visual model showing the likely locations for the electrons in an atom.
  10. 20. Neutral subatomic particle found in the nucleus.
Down
  1. 1. The action of purifying a liquid
  2. 3. Versions of the same element with different numbers of neutrons.
  3. 4. Observations & measurements recorded.
  4. 5. Having uniform composition throughout.
  5. 7. Matter that is physically combined or blended.
  6. 11. Any compound resulting from one or more elements.
  7. 13. Negatively charged subatomic particle found outside the nucleus.
  8. 15. The smallest particle of an element.
  9. 17. Dense, positively charged mass at the center of an atom.
  10. 19. An atom with a charge.