Across
- 4. No electron.
- 6. Checks if it's hot or cold.
- 8. All matter and energy, including Earth.
- 9. Appears around atomic nuclei.
- 10. Helps people breathe.
- 11. Light invisible to people eyes.
- 12. To join together.
- 15. Uses glass lens to magnify small objects.
Down
- 1. A stream of high-speed charged particles.
- 2. Atoms that all have same atomic number.
- 3. A negative charge atom.
- 5. Gas surrounding Earth.
- 7. Clouds of fine, solid particles.
- 13. Small particle.
- 14. A colorless, odorless inert gaseous.