Question Detail
Question
What is the correct formula when Mg2+ combines with O2-?
Correct Answer
Option D is the correct answer.
Detailed Explanation
When Mg2+ combines with O2-, the formula is MgO, not Mg2O2, because the subscripts are divided by the greatest common factor to get the lowest whole-number ratio.
Hint
The notes use this exact example to show the rule application.