1. Which of these show a diatomic element? 
CO 
H₂
 He 
SO₂ 
2. Which of these substances is an element? 
Chlorine 
Ice 
Methane 
Sodium chloride
 3. When the elements lead and bromine combine together, the name of the substance formed is called .......
 Lead bromate 
Lead bromide
 Lead bromite
 Lead bromium