Question

Which of the following does not represents a polyatomic ion?

• A. Chloride
• B. Sulphite
• C. Phosphate
• D. Sulphate

Answer 1

The correct option is A Chloride

A polyatomic ion is an ion composed of more than one atoms.
Sulphite, sulphate and phosphate ions are polyatomic as they contain more than one atoms. However, Cl^- is a monoatomic ion as it is composed of only chlorine atom. Ions with their formula and charge is given in the following table:
$$\begin{array}{ccc}\text{Ion}& \text{Formula}& \text{Charge}\\ \text{Sulphite}& (S{O}_3{)}^{2-}& \text{-2}\\ \text{Sulphate}& (S{O}_4{)}^{2-}& \text{-2}\\ \text{Phosphate}& (P{O}_4{)}^{3-}& \text{-3}\\ \text{Chloride}& (Cl{)}^{-}& \text{-1}\end{array}$$