Across
- 4. A gas that shares its name with Superman's home planet
- 7. Makes up about 78% of Earth's atmosphere
- 8. A radioactive element used in nuclear power and weapons
- 12. A metal essential for blood, symbol Fe
- 14. A radioactive element named after a dwarf planet
- 15. A precious yellow metal, symbol Au
- 16. A semiconductor material found in computer chips
- 18. A metal with a blue tint, symbol Co
Down
- 1. A metal symbolized by Sn, used in cans and alloys
- 2. The basis of organic chemistry and life
- 3. The lightest and most abundant element in the universe
- 5. A light metal used in rechargeable batteries
- 6. An inert gas commonly used in balloons
- 9. An inert gas in the atmosphere and used in light bulbs
- 10. The only metal that is liquid at room temperature
- 11. A metal used to galvanize steel and prevent rust
- 13. Essential for combustion and respiration
- 17. A heavy metal once used in pipes and paint