Question

Thinking back to writing formulas, what does the 3 on the outside of the bracket tell us?

A) The number of atoms
B) The charge of the ions
C) The coefficient of the compound
D) The mass of the molecule

Answer 1

The '3' outside the brackets in a chemical formula signifies the presence of three of that particular polyatomic ion within the compound.

Step-by-step explanation:

The 3 on the outside of the bracket in a chemical formula indicates how many of that particular polyatomic ion are present in the compound. If a chemical formula has something like (OH)3, this would mean that there are three hydroxide ions in the compound. Each polyatomic ion is surrounded by parentheses to indicate that it is a distinct entity within the compound, and the subscript outside the parentheses tells us the quantity of those ions that combine with the rest of the compound to maintain electrical neutrality.