MgBr MgBr_{2} Mg_{2}Br Mg_{3}Br_{2}
I gave my students this multiple choice question: Magnesium bromide is one of the most abundant compounds found in sea water. Which formula correctly represents magnesium bromide?

Only one answer is correct among these 4 choices:
- MgBr
- MgBr_{2}
- Mg_{2}Br
- Mg_{3}Br_{2}

Could you tell me which one is correct?

MgBr_{2}