Science assignment

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Across
  1. 2. Chemical reaction that releases energy
  2. 5. Catalyst involved in chemical reactions in living things
  3. 6. substance that helps a chemical reaction to proceed more quickly
  4. 7. Atom that has become electrically charged because it has lost or gained electrons
  5. 9. Element that has both metallic and non-metallic properties
  6. 11. A neutral substance is neither an acid nor a base
  7. 12. Principle that matter is not created or destroyed in a chemical reaction
  8. 14. dull, brittle element that does not conduct electricity
  9. 16. Change that results when two or more substances react to create a different substance or substances
  10. 20. Pure substance that cannot be broken down into other substances
  11. 21. Positively charged center of an atom that contains protons and neutrons
  12. 22. Slow chemical change occurs when oxygen in the air reacts with metal
  13. 24. Group 17 elements in the periodic table, the most reactive non-metals
  14. 25. invisible negatively charged particle that orbits the nucleus o an atom
Down
  1. 1. An experiment in which all reactants and all products of a chemical reaction are accounted for
  2. 3. Chemical reation that occurs when oxygen reacts with a substance to from an new substance and give off energy
  3. 4. Mass of one atom of an element calculated from the total number of protons neutrons and electrons of that atom
  4. 8. An experiment in which one or more products of a chemical reaction can escape
  5. 10. A table in which the elements are organized by their physical and chemical properties
  6. 12. A reaction that takes place when two or more substances react to from a new substance
  7. 13. Number of protons in the nucleus of one atom of an element
  8. 15. shiny, malleable, ductile, elements that conduct electricity
  9. 17. A chemical reaction that absorbs energy
  10. 18. Group 18 elements in the periodic table of elements that is most stable and unreactive elements
  11. 19. Chemical combination of two or more elements in a specific ratio
  12. 23. Substance that reacts with another substance or substances in a chemical reaction to create new substances with other substances