atoms and matter

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Across
  1. 3. smallest unit of an element that keeps the properties of the element
  2. 5. elements that have properties of both metals and nonmetals
  3. 8. states that matter cannot be created or destroyed
  4. 10. made of two or more atoms
  5. 11. made of two or more different atoms
  6. 14. one group of elements that are unreactive
  7. 15. horizontal row of elements, tells you the number of shells
  8. 16. positively charged particle in the center of the atom
  9. 17. can have a chemical reaction with another substance
  10. 21. a mixture where one of the substances dissolves in the other, looks uniform
  11. 22. dense, positively center of an atom
Down
  1. 1. neutrally charged particle in the center of the atom
  2. 2. The electrons on the outermost shell of the atom
  3. 4. the amount of space an object takes up
  4. 6. easily set on fire
  5. 7. combination of 2 or more substances not chemically combined
  6. 9. the system of electrons surrounding the nucleus of an atom
  7. 12. Substance made of only one type of atom or only one type of molecule
  8. 13. measure of the amount of mass in a given volume
  9. 18. number number of protons in the nucleus
  10. 19. a charged particle that forms when an atom gains or loses one electrons
  11. 20. A vertical column on the Periodic Table of Elements