CsCl CsCl_{2} CsO CsO_{2}
I gave my students this multiple choice question: The element cesium, Cs, is an alkali metal. Which chemical formula represents a cesium compound that is likely to exist?

Only one answer is correct among these 4 choices:
- CsCl
- CsCl_{2}
- CsO
- CsO_{2}

Could you tell me which one is correct?

CsCl