| A | B |
|---|
| hydrogen | 1, H |
| helium | 2, He |
| Lithium | 3, Li |
| Beryllium | 4, Be |
| Boron | 5, B |
| Carbon | 6, C |
| Nitrogen | 7, N |
| Oxygen | 8, O |
| Fluorine | 9, F |
| Neon | 10, Ne |
| Sodium | 11, Na |
| Magnesium | 12, Mg |
| Aluminum | 13, Al |
| Silicon | 14, Si |
| Phosphorus | 15, P |
| Sulfur | 16, S |
| Chlorine | 17, Cl |
| Argon | 18, Ar |
| Potassium | 19, K |
| Calcium | 20, Ca |
|
