Unit 2 review

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Across
  1. 3. Using various scientific ________, scientists have determined the atomic mass of every element
  2. 5. electrons have almost no __________
  3. 7. the _____ number comes almost entirely from the mass of the protons + the mass of the neutrons
  4. 10. atoms that are missing ______or have extra ____ are called ions
  5. 12. inside the nucleus are 2 types of particles; the neutorn and the _____
  6. 13. Protons carry a _________ charge
  7. 14. H2O and O2 are examples of _____ molecules
Down
  1. 1. ______is the region in the center of an atom
  2. 2. each element has a number assigned to it called the _____ number
  3. 4. the number of protons is ____ to the number of electrons when an atom is in an uncharged state
  4. 6. The far right side of the periodic table contains a family called the noble ______
  5. 8. an____is the smallest piece of an element
  6. 9. The _____ table of the elements is arranged according to the element's atomic number
  7. 11. A____ is defined by 2 or more atoms joined together