What is formed when chlorine combines with oxygen atoms?

• A. Chlorine dioxide (ClO2)
• B. Chlorine monoxide (ClO)
• C. Chlorine trifluoride (ClF3)
• D. Dichlorine (Cl2)

Answer: (B)

When chlorine combines with oxygen atoms, the correct compound that is formed is chlorine monoxide (ClO). This molecule consists of one chlorine atom and one oxygen atom, which allows it to be categorized as a monoxide.

Chlorine monoxide plays a notable role in atmospheric chemistry, particularly in reactions involving ozone depletion. It is an important intermediate species in the stratospheric reactions that can lead to the breakdown of ozone.

In this context, chlorine dioxide (ClO2) is a different molecule that contains two oxygen atoms. Chlorine trifluoride (ClF3) is a compound formed with fluorine, not oxygen, and dichlorine (Cl2) refers to the diatomic form of chlorine, which contains only chlorine atoms. Thus, they do not represent the combination of chlorine and oxygen correctly as chlorine monoxide does.