Unit 1 Vocabulary: Investigating Atoms and the Periodic Table

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Across
  1. 5. a particle smaller than an atom, such as a proton, neutron, or electron
  2. 8. property – property of matter that can be observed without changing the composition or identity of the matter
  3. 15. An element whose properties are intermediate between those of metals and solid nonmetals or semiconductors.
  4. 16. a unit of mass used to express atomic and molecular weight
  5. 19. a pure substance that cannot be broken down chemically into simpler substances
  6. 20. a characteristic of a substance that describes how it combines with other substances to form new ones
  7. 21. Metals that have more than one oxidation state
  8. 22. a negatively charged particle in the electron cloud surrounding the atomic nucleus
  9. 24. the positively charged center of an atom containing the protons and neutrons
  10. 25. the vertical columns on the Periodic Table
Down
  1. 1. a conceptual model in which the elements are organized according to their properties; often displayed as a chart
  2. 2. a (neutral) particle with no electrical charge within the atomic nucleus
  3. 3. tendency of a substance to undergo chemical changes in a system
  4. 4. a positively charged particle within the atomic nucleus; used to identify an element
  5. 6. average mass number of all atoms of an element (from particles in the nucleus)
  6. 7. total number of protons and neutrons in a specific atom
  7. 9. Elements that lack any metallic characteristics
  8. 10. an element that readily forms positive ions (cations) and has metallic bonds
  9. 11. any of the elements lithium, sodium, potassium, rubidium, cesium, and francium, occupying Group IA (1) of the periodic table. They are very reactive, electropositive, monovalent metals forming strongly alkaline hydroxides.
  10. 12. the negatively charged space containing electrons that surrounds the atomic nucleus
  11. 13. the number of protons in the nucleus of an atom; used to determine an element's position in the Periodic Table
  12. 14. charge a property of a subatomic particle; positive (protons), negative (electrons), or neutral (neutrons)
  13. 17. electrons located in outer energy level (electron shell)
  14. 18. the horizontal rows on the Periodic Table
  15. 23. smallest particle of an element that maintains the properties of that element
  16. 24. any of a group of rare gases that include helium, neon, argon, krypton, xenon, and usually radon and that exhibit great stability and extremely low reaction rates