Across
- 2. it has 1 oxygen and 2 hydrogen
- 6. 1st element in periodic table
- 7. reacts with base
- 8. most toxic element
- 9. most used element in the world
Down
- 1. it mixed with gold to make jewel
- 3. rarest element
- 4. expansive element
- 5. 1st nobel gas in periodic table