Question

multiple-choice question
why are there no parentheses in this formula?
because there are no polyatomic ions.
because there is only one carbonate, so it is not needed.
rewatch

Explanation:

Parentheses are used in ionic compound formulas to enclose polyatomic ions when there is more than one of that polyatomic ion in the formula. If only one polyatomic ion (like carbonate here) is present, parentheses are unnecessary as the subscript 1 (implied) clearly indicates a single unit of the polyatomic ion. The first option is incorrect because carbonate is a polyatomic ion, so the formula does involve a polyatomic ion.

Answer:

Because there is only one carbonate, so it is not needed.