Chemistry project

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Across
  1. 1. Gas Stable, non-reactive element in Group 18.
  2. 4. Atomic number of phosphorus.
  3. 5. the smallest unit of matter that makes up elements.
  4. 6. 2 Ion with two positive charges.
  5. 7. Electrons in the outermost shell.
  6. 8. number number of protons in an atom.
Down
  1. 2. Negative particle orbiting the nucleus.
  2. 3. Vertical columns on the periodic table.
  3. 6. Horizontal rows on the periodic table.
  4. 9. Two or more elements chemically combined.