He

(a)  

Lithium

(a)  

Beryllium

(a)  

Boron

(a)  

C

(a)  

N

(a)  

Oxygen

(a)  

Fluorine

(a)  

Neon

(a)  

Sodium

(a)  

Mg

(a)  

Al

(a)  

Silicon

(a)  

P

(a)  

S

(a)  

Chlorine

(a)  

Argon

(a)  

Potassium

(a)  

Ca

(a)  

Fe

(a)  

Copper

(a)  

Mercury

(a)  

Silver

(a)  

Gold

(a)