2. Helium?
3. Lithium
4. Really?
5. Boron
6. Carbon
7. Nitrogen
8. Oxygen
9. fluorine
10. Neon light
1 1. sodium
12. Magnesium
13. aluminum?
14. Silicon
15. Phosphorus?
16. Sulfur
17. Chlorine
18 argon?
19. Potassium
20. Calcium
2 1. scandium
22. Titanium
23. vanadium
24. Chromium?
25. Manganese?
iron
cobalt
Extended data:
Memory method of periodic table of elements;
Oxygen is O, and phosphorus is the symbol of P and Mg.
Symbol Fe Na Na Na Pb Pb Fe
The symbol of gold, gold, silver, silver and platinum is platinum.
Symbol Hg for aluminum, aluminum, beryllium and mercury
Potassium is k, boron is tHe symbol of b helium, he.
Iodine is the symbol Se of iodine, neon, neon and selenium.
Ca, Ca, Cl, Cl, Cu, Cu, c is C.
The symbol of sulfur s, fluorine f and hydrogen is H.
Nitrogen is the symbol Mn of nitrogen, zinc, zinc and manganese.
Symbols of nickel, nickel, silicon, silicon and lithium.
Ar, Ar, Br, Br and Kr are symbols of Kr.