chap 16

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Across
  1. 2. the number of protons in the element
  2. 5. the vertical columns in the periodic table
  3. 7. the horizontal rows in the periodic table
  4. 11. the weighted-average mass of the mixture of its isotopes
  5. 14. the smallest piece of matter that still retains the properties of the element
  6. 15. particles with a positive 1 charge
  7. 16. area around the nucleus of an atom where its electrons are most likely found
Down
  1. 1. small positively charged center of the atom. contains the protons and neutrons
  2. 3. uses the symbol of the element and dots to represent the electrons in the outer energy level
  3. 4. particles that have 0 charge
  4. 6. neutral particles that have 0 charge
  5. 8. atoms of the same element that have different numbers of neutrons. (different mass numbers)
  6. 9. protons and neutrons are made of even smaller particles called ......
  7. 10. the elements are arranged by increasing atomic number and by changes in physical and chemical properties
  8. 12. particles with a negative 1 charge
  9. 13. the sum of the protons and the neutrons in the element