Across
- 5. - Second most abundant element in Earth's crust
- 7. - Essential for respiration
- 8. - Makes up 78% of Earth's atmosphere
- 12. - Nonmetal used in ceramics and electronics
- 13. - Noble gas, second most abundant in the universe
- 15. - Found in bones and DNA
- 16. - Essential for bones and teeth
- 18. - Used in matches and gunpowder
- 19. - Used in signs and lamps
Down
- 1. - Most electronegative element
- 2. - Highly conductive, used in cans
- 3. - Essential for biological processes
- 4. - Lightest element, most abundant in the universe
- 6. - Corrosion-resistant metal, used in alloys
- 9. - Used in alloys and pyrotechnics
- 10. - Essential for plant and animal life
- 11. - Used to disinfect water
- 14. - Used in light bulbs and welding
- 16. - Found in all organic compounds
- 17. - First alkali metal, used in batteries