Potassium (K) and Rubidium (Rb) forms

Superoxides

The correct answer is (3) Superoxides.

Potassium (K) and Rubidium (Rb) form superoxides.

Superoxides are compounds that contain the superoxide ion, \(O^{2-}_2\). The superoxide ion is a very reactive species, and it is responsible for the strong oxidizing properties of superoxides.

The chemical formulas for potassium superoxide and rubidium superoxide are \(KO_2\) and \(RbO_2\), respectively.

The other options are incorrect:

• Suboxides are compounds that contain less oxygen than the stoichiometric oxide of the element.
• Peroxides are compounds that contain the peroxide ion, \(O^{2-}2\).
• Dioxides are compounds that contain two oxygen atoms per metal atom.