In short, we put parentheses to make it clear that there's multiple of some group of elements, such as a polyatomic ion here, in a chemical formula. It's not needed for singular elements.

We know this is a long list of ions, but there are actually patterns to how many of these polyatomic ions are named. Learning these patterns will be far more helpful to you in remembering the …

Polyatomic ions combine with other ions in a ratio that produces a neutral compound overall. Subscripts are used to indicate the number of ions needed to make that neutral compound.

Naming ionic compounds Google Classroom Microsoft Teams You might need: Periodic table

Reviewing the common polyatomic ions, and explaining common suffixes and prefixes to help remember the formulas.

Learn how to name positive ions (cations), negative ions (anions), and ionic compounds involving main group elements.

Reviewing the common polyatomic ions, and explaining common suffixes and prefixes to help remember the formulas.

Learn how to name monatomic ions and ionic compounds containing monatomic ions, predict charges for monatomic ions, and understand formulas.

Let's review the common polyatomic ions, and look at the common suffixes and prefixes to help remember the formulas.

Naming ionic compounds that contain polyvalent ions, using example of cobalt (III) sulfide.