1   hydrogen H
2   helium He
3   lithium Li
4   berillium   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   aluminum   Al      
14   silicon   Si            
15   phosphorus  P      
16   sulphur  S          
17   chlorine   Cl     
18   argon   A