atoms and chemical reaction

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Across
  1. 2. what is a chemical reaction
  2. 5. a substance made up of only one type of atom
  3. 8. a chemical reaction which a compound breaks down into two or more
  4. 10. the rate at which reactants change into products over time
  5. 13. the number of protons in a nucleus
  6. 14. what has a neutral charge
  7. 16. a chemical reaction in which two or more substances react to form a single substances
  8. 18. what is a physical change
  9. 19. new substance formed as a result of a chemical reaction
  10. 20. what is the smallest unit of an element
Down
  1. 1. three substances particles in the nucleus
  2. 3. a chemical reaction in which electrons are transferred from one reactant to another
  3. 4. what is a substance to be deposited in solid form from a solution
  4. 6. a molecule made of repeating units formed into long chains
  5. 7. where is the protons located
  6. 9. what is located at the center of an atom
  7. 11. what is located in the electron cloud
  8. 12. what is located in nucleus and has a positive charge
  9. 15. a substance that undergoes change in a chemical reaction
  10. 17. a pure substance that is made up of two or more different types of atoms chemically joined