Chemistry!!

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Across
  1. 4. the simplest structural unit of an element or compound
  2. 5. is an atom or molecule that has gained or lost one or more electrons.
  3. 6. the smallest component of an element
  4. 7. electron are the atom's outermost electrons.
  5. 9. is a group of elements sharing similar properties.
  6. 10. a subatomic particle with zero charge
Down
  1. 1. a stable particle with positive charge
  2. 2. A negatively charged particle that comprises the external part of the atom
  3. 3. a row (left to right) of the periodic table.
  4. 8. relating to or containing an alkali