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