Across:
1. Thorium
2. Arsenic
3. Zirconium
4. Lithium
5. Bromine
6. Tin
7. Calcium
8. Nickel
9.Carbon
10. Gold
11. Radium
12. Potassium
13. Chlorine
14. Manganese
15. Francium
16. Mercury
17. Nitrogen
18. Neon
19. Platinum
20. Hydrogen
21. Lead
22. Cobalt
23. Oxygen
24. Fluorine
Down:
1. Titanium
2.Argon
3. Zinc
4. Lanthanum
5. Barium
6. Silicon
7. Copper
8. Sodium
10. Aluminum
11. Radon
12. Krypton
14. Magnesium
15. Iron
16. Helium
18. Niobium
19. Polonium