Easy enough explanation on polyatomic ions?

A polyatomic ion simply means there are two or more atoms bonded together that have an overall charge. For example, nitrate is NO31-, which means 1 atom N and 3 atoms O are bonded together and overall the number of electrons is one greater than the total number of protons in the group, giving it an overall charge of 1-.

Many polyatomic ions contain oxygen. The formulas of polyatomic ions, including their charges, must be memorized. Your instructor should tell you which ones to memorize. Some common polyatomic anions ( - ions) are:

nitrate: NO31-
nitrite: NO21-
sulfate: SO42-
sulfite: SO32-
carbonate: CO32-
acetate: C2H3O21-
chlorate: ClO31-
phosphate: PO43-
hydroxide: OH1-
cyanide: CN1-
bicarbonate (or hydrogen carbonate): HCO31-
bisulfate (or hydrogen sulfate): HSO41-
chromate: CrO42-
permanganate: MnO41-
dichromate: Cr2O72-

The only common polyatomic cation (+ ion) is ammonium: NH41+.

To memorize these ions, cut recipe cards in half. On one side of each card write the formula of the polyatomic ion; on the flip side wirte its name. Put a rubber band around these and carry them with you. When you have a minute or two, practice on learning the names of the formulas and also on learning the formulas for the names.