Across
- 5. A covalent compound
- 7. A halogen
- 8. positive ion
- 11. an alkaline earth metal
- 12. the numbers of protons
- 13. an actinide
- 15. gave modern periodic table
Down
- 1. A metalloid
- 2. liquid metal
- 3. negative ion
- 4. first one to define atoms
- 6. A negatively charged particle
- 9. An ionic compound
- 10. A positively charged particle
- 14. A transition metal