Science Vocab. Unit 1

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Across
  1. 2. the horizontal rows on the Periodic Table
  2. 5. The number of protons in the nucleus of an atom; used to determine an element's position in the Periodic Table
  3. 7. cloud the negatively charged space containing electrons that surrounds the atomic nucleus
  4. 8. (families)the vertical columns on the Periodic Table
  5. 14. property of matter that can be observed without changing the composition or identity of the matter
  6. 18. A characteristic of a substance that describes how it combines with other substances to form new ones
  7. 19. Average mass number of all atoms of an element (from particles in the nucleus)
Down
  1. 1. a property of a subatomic particle; positive (protons), negative (electrons), or neutral (neutrons)
  2. 3. a particle smaller than an atom, such as a proton, neutron, or electron
  3. 4. Smallest particle of an element that maintains the properties of that element
  4. 6. a negatively charged particle in the electron cloud surrounding the atomic nucleus
  5. 9. conceptual model in which the elements are organized according to their properties; often displayed as a chart
  6. 10. electron(s) located in outer energy level (electron shell)
  7. 11. tendency of a substance to undergo chemical changes in a system
  8. 12. number – total number of protons and neutrons in a specific atom
  9. 13. a positively charged particle within the atomic nucleus; used to identify an element
  10. 15. a (neutral) particle with no electrical charge within the atomic nucleus
  11. 16. the positively charged center of an atom containing the protons and neutrons
  12. 17. a pure substance that cannot be broken down chemically into simpler substances