Atomic No. Name Symbol Valency
1 Hydrogen H 1
2 Helium He 0
3 Lithium Li 1
4 Beryllium Be 2
5 Boron B 3
6 Carbon C 4
7 Nitrogen N 3
8 Oxygen O 2
9 Flourine F 1
10 Neon Ne 0
11 Sodium Na 1
12 Magnesium Mg 2
13 Aluminium Al 3
14 Silicon Si 4
15 Phosphorus P 3,5
16 Sulphur S 2
17 Chlorine Cl 1
18 Argon Ar 0
19 Potassium K 1
20 Calcium Ca 2