Atoms and the Periodic Table Vocabulary

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Across
  1. 3. highly reactive metals in Group 1
  2. 7. number of electrons in the outermost energy level
  3. 8. atoms of the same element with different mass numbers due to different numbers of neutrons
  4. 10. equal number of protons and electrons
  5. 13. equals the number of protons
  6. 14. found in Group 4A (14) and includes a major element found in living things
  7. 19. a pure substance that cannot be broken down into anything smaller
  8. 21. dull, brittle solids or gases; found on the upper right side of the Periodic Table
  9. 22. surrounds the nucleus
  10. 23. a negatively charged subatomic particle found in the electron cloud
  11. 24. vertical columns on the periodic table that tells how many valence electrons each atom has
Down
  1. 1. shows chemical elements arranged in order of atomic number
  2. 2. extremely reactive gases of Group 7A (17)
  3. 4. smallest particle of an element
  4. 5. reactive Group 2 with two valence electrons
  5. 6. number of protons and neutrons for all isotopes of an element
  6. 9. average number of protons and neutrons in one atom
  7. 11. find the number by subtracting the atomic number from the mass number
  8. 12. groups 3-12 that are shiny and good conductors
  9. 15. a positively charged subatomic particle consisting of half the nucleus' mass
  10. 16. the letter(s) that represent an element on the periodic table
  11. 17. elements between metals and nonmetals, found on the stair step line
  12. 18. horizontal rows on the periodic table that also tells how many energy levels are present
  13. 19. it's identity is determined by the atomic number, the element number, and the number of protons in the atom
  14. 20. contains protons and neutrons