First 20 Elements of the Periodic Table

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Across
  1. 5. Right of the Metalloid Staircase
  2. 7. B
  3. 8. Cl
  4. 10. Ca
  5. 12. C
  6. 13. Title of the second last Group
  7. 15. Title of the second Group
  8. 16. Na
  9. 17. Ne
  10. 20. H
  11. 21. K
  12. 22. On the Metalloid Staircase
  13. 23. Al
  14. 25. Title of the last Group
Down
  1. 1. F
  2. 2. O
  3. 3. Si
  4. 4. Title of the first Group
  5. 6. Ar
  6. 7. Be
  7. 9. Mg
  8. 11. Left of the Metalloid Staircase
  9. 14. N
  10. 18. P
  11. 19. S
  12. 20. He
  13. 24. Li