chemistry

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Across
  1. 2. A simple substance that cannot be broken down into smaller pieces
  2. 3. The basic unit of a chemical element
  3. 6. A thing that is composed of two or more separate elements ( a mixture)
  4. 7. A constant related to the properties of a product
  5. 8. A positive charge region at the center of the atom
  6. 9. A large body of matter with no definite shape
Down
  1. 1. A subatomic particle with a negative charge
  2. 4. A subatomic particle occuring in a atomic nuclei
  3. 5. A group of atoms bonded together
  4. 7. A system of electron surrounding the nucleus