What is the charge of hydroxide (OH)?

The hydroxide ion (OH) carries a charge of -1. This negative charge arises from the fact that oxygen typically has a valence of -2 and hydrogen a valence of +1. When they combine to form hydroxide, the overall charge is determined by the sum of their individual charges. Here, the oxygen's -2 charge is balanced by the hydrogen's +1 charge, resulting in the ion having a net charge of -1. This charge is significant in many chemical reactions and interactions, particularly in acid-base chemistry, as hydroxide is a common base that can accept protons (H+) to form water (H2O). Understanding the charge of hydroxide is vital for predicting how it will behave in various chemical contexts.