feleeieie ice chap 16

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