Hydrogen
H, 1
Helium
He, 2
Lithium
Li, 3
Beryllium
Be, 4
Boron
B, 5
Carbon
C, 6
Nitrogen
N, 7
Oxygen
O, 8
Fluorine
F, 9
Neon
Ne, 10
Sodium
Na, 11
Magnesium
Mg, 12
Alumunium
Al, 13
Silicon
Si, 14
Phosphorus
P, 15
Sulfur
S, 16
Chlorine
Cl, 17
Argon
Ar, I8
Potassium
K, 19
Calcium
Ca, 20