Polyatomic Ions are defined as which of the following?

• A. A mixture of atoms with charge
• B. A single atom with a charge
• C. A neutral molecule formed by atoms
• D. Groups of atoms that stay together and have an overall charge. The name usually ends in -ate or -ite

Answer: (D)

Polyatomic ions are groups of two or more atoms that stay bonded together and have a net electric charge. They act as a single unit in ionic compounds, which is why you’ll often see their names ending in -ate or -ite for many of the common oxyanion ions, like sulfate (SO4^2−), nitrate (NO3^−), and carbonate (CO3^2−). It’s also good to remember there are polyatomic cations, such as ammonium (NH4^+), showing the charge can be positive or negative.

The other ideas don’t fit because a mixture of atoms isn’t bound as one unit, a single atom with a charge describes a monoatomic ion, and a neutral molecule formed by atoms has no overall charge. The defining feature of a polyatomic ion is multiple atoms bonded together acting as one charged unit.