Ch 4 Cross Word

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Across
  1. 2. he noticed that a pattern of properties appeared when elements were arranged in order of increasing atomic mass
  2. 4. the center of an atom
  3. 5. particle with no electrical charge
  4. 6. the vertical columns of the periodic table
  5. 7. atoms of the same element that have a different number of neutrons
  6. 9. the ______ number is the sum of the protons and neutrons
  7. 10. the _______ number is the number of protons in the nucleus of an atom
Down
  1. 1. the horizontal rows of the periodic table
  2. 3. the negatively charged particle
  3. 8. the positively charged particle