Unit 2 Vocab.

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Across
  1. 3. reaction that absorbs energy
  2. 7. a group of two more atoms held together by a chemical bond
  3. 10. substance formed as a result of a chemical reaction
  4. 13. shows the number and types of atoms present in a molecule
  5. 14. an arrangement of the elements
  6. 16. shows the reactants and the products, separated by an arrow
  7. 18. created or manufactured by humans
  8. 20. substance(s) that enter into a chemical reaction
Down
  1. 1. anything naturally occurring in the environment that humans use
  2. 2. one or two letter abbreviation of an element
  3. 4. reaction that releases energy, usually in the form of heat
  4. 5. one or more substances combine or break down to form new substances
  5. 6. number of protons in the nucleus of an atom
  6. 8. matter is not created or destroyed in any chemical reaction
  7. 9. substance made of only one type of atom
  8. 11. small sized number representing the number of atoms of that element
  9. 12. a substance made of two or more elements
  10. 15. positively charged center of an atom
  11. 17. alters the form/appearance of matter
  12. 19. basic unit of matter