Periodic Table Crossword

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Across
  1. 4. _____electron- an electron in the outer layers of the electron cloud
  2. 5. ______elements- made in laboratories and nuclear reactors
  3. 9. ______elements- eight groups of elements in the periodic table
  4. 13. atomic_____-the number of protons in the nucleas of an atom of that element
  5. 15. _____gases- unreactive gases, always found on their own in nature
  6. 16. neutral charge, same mass as proton, in the nucleus
  7. 18. a substance that can make something happen faster but does not change itself
  8. 20. matter made of only one kind of atoms
Down
  1. 1. ______elements- groups 3 to 12 in the periodic table
  2. 2. row of elements in the periodic table whose properties change gradually and predictably
  3. 3. atomic_____-the weight of each element
  4. 6. ______cloud- a region surrounding the nucleus
  5. 7. an element that shares some properties with metals and some with nonmetals
  6. 8. contains elements that have similar or physical chemical properties
  7. 10. doesnt conduct electricity as well as a metal, but does conduct electricity better than a nonmetal
  8. 11. usually gases or brittle solids at room temperature and poor conductors of heat and electricity
  9. 12. _____Earth metals- fairly reactive metals, never found uncombined in nature
  10. 14. positively charged particle in nucleus
  11. 17. element that has luster, is a good conductor of heat and electricity, and is ductile
  12. 19. _____metals- highly reactive metals