Periodic Table

1234567891011121314151617181920
Across
  1. 2. group 18
  2. 6. group 1
  3. 7. Atoms of the same element that have different number of neutrons
  4. 9. group 3-12
  5. 10. group 17
  6. 12. where electrons are located
  7. 16. Elements 57-71
  8. 17. elements located on tops of the staircase
  9. 19. discovered nucleus
  10. 20. the number of protons in an atom
Down
  1. 1. positively charged particles
  2. 3. group 2
  3. 4. neutrally charged particles
  4. 5. elements on the left side of periodic table
  5. 8. negatively charged particles
  6. 11. center of an atom
  7. 13. elements on the right side of periodic table
  8. 14. elements 89-103
  9. 15. arranged elements by atomic number
  10. 17. Arranged elements by increasing atomic mass
  11. 18. total number of protons and neutrons