Chapter 9 Matter is made of atoms

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Across
  1. 3. have a negative electrical charge (-)
  2. 5. an atom that carries
  3. 6. two atoms with different numbers of nuetrons
  4. 7. have a positive charge (+)
Down
  1. 1. electrons an electron in the outermost energy level of an atom
  2. 2. weight average mass of naturally occurring isotopes of an element
  3. 3. levels any of the possible energies an electron may have in an atom
  4. 4. have no electrical charge