Across
- 2. used in balloons.
- 4. atomic number is 18.
- 6. makes your teeth pretty, used in toothpaste.
- 8. helps us breath.
- 9. used in fluorescent lamps and signs.
Down
- 1. a soft-white reactive metal.
- 2. highly flammable gas, chemical element of atomic number is 1
- 3. a non metal which has 2 forms,diamond and graphite.
- 5. a irritant, pale green gas.
- 7. atomic number is 5.