which is an example of a polyatomic ion?\no h₂\no co₃⁻\no mg⁺\no ne⁺

Answer:

B. $CO_3^{-}$

Explanation:

Step1: Define polyatomic ion

A polyatomic ion is an ion composed of more than one atom.

Step2: Analyze each option

• $H_2$ is a molecule, not an ion.
• $CO_3^{-}$ is composed of carbon and oxygen atoms and is an ion, so it is a polyatomic ion.
• $Mg^{+}$ is a monatomic ion (formed from a single magnesium atom).
• $Ne^{+}$ is a monatomic ion (formed from a single neon atom).