Chemical compounds with two oxygen atoms per molecule are known as...

• A. Dioxides
• B. Peroxides
• C. Hydrides
• D. Sulfides

Answer: (A)

In chemical naming of oxides, the number of oxygen atoms per formula unit is shown by the ending of the name. A compound with two oxygen atoms per molecule is called a dioxide. This naming pattern is why carbon dioxide, sulfur dioxide, and nitrogen dioxide are named with the suffix -dioxide. The other terms describe different ideas: peroxides involve an O–O bond and aren’t simply two oxygens attached to the central element, while hydrides and sulfides refer to compounds where hydrogen or sulfur are the main constituents, not specifically about having two oxygens. So the term that correctly matches two oxygens per molecule is dioxide.