Across
- 1. hard metalloid
- 3. brittle yellow solid
- 4. lightweight non-corroding metal
- 6. explosive gas, lightest element
- 7. soft metal, reactive nerves, nutrient in fruits and vegetables
- 9. colorless gas 25 percent of air
- 11. yellowish poison gas, most reactive element
- 15. inert gas, 1 percent of air
- 16. hard black solid
- 17. soft lightweight metal
- 18. lightest metal, soft, reactive
- 20. lightweight metal
- 21. soft metal, reactive
Down
- 2. soft metal, bones, teeth, milk
- 5. greenish poison gas
- 7. glowing white waxy solid (also red and black forms)
- 8. alloys, racing bikes, stadium lamps, furnace bricks,
- 10. colorless gas
- 12. inert gas
- 13. lightweight metal
- 14. hard diamond, soft graphite
- 19. inert gas, second-lightest element