2
Helium
3
Lithium
4
Beryllium
5
Boron
6
Carbon
7
Nitrogen
8
Oxygen
9
Fluorine
10
Neon
11
Sodium
Na
12
Magnesium
Mg
13
Aluminium
Al
14
Silicon
Si
15
Phosphorous
P
16
Sulfur
S
17
Chlorine
Cl
18
Argon
Ar
19
Potassium
K
20
Calcium
Ca
21
Scandium
Sc
22
Titanium
Ti
23
Vanadium
V
24
Chromium
Cr
25
Manganese
Mn