Across
- 3. 20 protons
- 6. neutrally charged
- 9. first element in period 4
- 12. Name for horizontal rows
- 14. group 1
- 15. groups 3-12
- 19. number of element
- 20. 1 proton
Down
- 1. 5 protons
- 2. center of an atom
- 4. negative charged
- 5. between metals and nonmetals
- 7. 10 protons
- 8. elements on the right of the periodic table
- 10. good conductors
- 11. first noble gas
- 13. group 17 name
- 16. smallest unit of matter
- 17. abbreviation is Ag
- 18. average mass of element