Answer
magnesium hydroxide
Work Step by Step
$Mg$ is the elemental symbol for magnesium.
$OH^-$ is the symbol for the ion hydroxide.
The two combine to form an ionic compound. Ionic compounds are named according to the following rules:
1. The cation is named first and is written as-is.
2. The anion is named second, and its ending is changed to $-ide$; however, since hydroxide already has the $-ide$ ending, we leave it as-is.
Therefore, the name of this compound is magnesium hydroxide.
