Units 1-3 Crosssword 2 2015

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Across
  1. 4. A substance that cannot be decomposed into simpler substances by chemical means, an atom that is defined by its atomic number
  2. 5. the metals of Group 1 on the periodic table
  3. 7. the process of an unstable atomic nucleus losing energy by emitting radiation
  4. 9. an orbital around the atom's nucleus that has a fixed number electrons (usually two or eight)
  5. 12. the metals of Group 2 on the periodic table
  6. 13. combining two small nucleus, creates energy
  7. 14. mixture of evenly dispersed substances
  8. 15. fuel made from decaying plants and animals
  9. 17. Anything that has mass and occupies space.
  10. 18. a chemical reaction between an oxidant and fuel with heat and often light
  11. 19. A change in which one or more new substances are formed.
  12. 20. atoms containing the same number of protons but different numbers of neutrons
  13. 21. columns on the period table, 1-18
Down
  1. 1. An atom or a group of atoms that carries an electric charge
  2. 2. a subatomic particle with a net charge that is negative
  3. 3. two or more substances combined
  4. 6. occurs in nature used for enjoyment, or is economically important
  5. 7. Mass per unit Volume, how tightly packed the particles are
  6. 8. a chemical element in its smallest form
  7. 10. ongoing series of fission reactions
  8. 11. Oxidation of metals in the presence of air and moisture.
  9. 15. split of a large nucleus, creates energy and radiation
  10. 16. a substance that is made up of two or more chemically bonded elements