Chemistry

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Across
  1. 1. Alkali metal that reacts vigorously with water
  2. 4. Left in Mendeleev’s table for undiscovered elements
  3. 5. Halogens, reactive non-metals
  4. 6. How easily an element reacts with others
  5. 8. Scientist who developed the early periodic table
  6. 12. Arrangement of electrons in an atom
  7. 14. Green halogen used in disinfectants
  8. 17. Lightest noble gas, used in balloons
  9. 19. Chemically unreactive, like noble gases
  10. 20. Vertical columns in the periodic table
  11. 21. Chart that organizes elements by atomic number and properties
  12. 23. Alkali metals, very reactive and soft
  13. 24. Allows heat or electricity to pass through
  14. 25. Reaction where a more reactive halogen replaces a less reactive one
Down
  1. 2. Prevents the flow of heat or electricity
  2. 3. Most reactive halogen
  3. 7. Number of protons in an atom’s nucleus
  4. 9. Elements that are good conductors and form positive ions
  5. 10. Can be hammered or bent into shape
  6. 11. Elements that are poor conductors and form negative ions
  7. 13. Patterns in properties across a group or period
  8. 15. Horizontal rows in the periodic table
  9. 16. First element in Group 1
  10. 18. Noble gases with full outer electron shells
  11. 22. Breaks or shatters easily under stress