SCIENCE - TERM 2

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Across
  1. 3. a metal that is important for bones and teeth.
  2. 5. something that happens in a regular, repeating pattern.
  3. 6. a radioactive metal that is used in nuclear reactors and weapons.
  4. 7. a reaction where two or more simple substances combine to form a more complex compound.
  5. 10. the smallest particle of a chemical element that can exist.
  6. 11. a reaction where a compound breaks down into two or more simpler substances.
Down
  1. 1. a lightweight metal with atomic number 13.
  2. 2. a rare and highly radioactive metal with atomic number 87.
  3. 4. a small, negatively charged particle that orbit the nucleus of an atom.
  4. 8. a pure substance made of only on kind of atom, listed on the periodic table.
  5. 9. a tiny, positively charged particle in an atom's nucleus.