Atoms and the Periodic Table

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Across
  1. 3. The name of a column on the periodic table.
  2. 4. a mixture where you cannot see the different parts.
  3. 5. The negative particle with no mass.
  4. 8. The term for an electron on the outside shell.
  5. 9. ______ Gases in Group 18 Elements
  6. 10. a hazardous material that reacts with oxygen.
  7. 11. Group 1 Elements
  8. 13. to find the number of neutrons: subtract the atomic number from the atomic ________.
  9. 15. the smallest unit of matter.
  10. 16. a hazardous material that can break down skin and clothing.
  11. 17. The neutral particle.
  12. 18. these are good conductors of heat and electricity. They are also shiny.
  13. 19. The name of a column on the periodic table.
  14. 21. The centre of an atom.
  15. 22. How much mass there is per unit volume.
Down
  1. 1. Metals are considered this if they can bend.
  2. 2. atoms always have the same number of protons and electrons, this is called the ________ number.
  3. 3. a property which can be determined without changing the chemical makeup.
  4. 4. The most reactive nonmetal group.
  5. 6. another word for a shell where electrons are found.
  6. 7. these have properties of both metals and nonmetals.
  7. 12. the abbreviation for atomic mass units.
  8. 13. Scientist who created the Periodic Table in 1869.
  9. 14. The positive particle found inside the nucleus.
  10. 16. made up of two or more elements combined.
  11. 20. How shiny something is.