2 Helium
He
1 Hydrogen
H
3 Lithium
Li
4 Beryllium
Be
5 Boron
B
6 Carbon
C
7 Nitrogen
N
8 Oxygen
O
9 Fluorine
F
10 Neon
Ne
11 Sodium
Na
12 Magnesium
Mg
13 Aluminium
Al
14 Silicon
Si
15 Phosphorus
P
16 Sulphur
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