* Polyatomic ions are groups of two or more atoms that are covalently bonded together and carry an overall positive or negative charge. Examples include sulfate (SO₄²⁻) and ammonium (NH₄⁺).
* Sodium chloride is an ionic compound formed by the electrostatic attraction between a positively charged sodium ion (Na⁺) and a negatively charged chloride ion (Cl⁻). It's not a single, covalently bonded group of atoms with a charge.
In summary: Sodium chloride is a simple ionic compound, not a polyatomic ion.
