Determine whether the polyatomic ion has a positive or negative charge. Memorizing the methods associated with polyatomic ions can be accomplished easily if you know the charge of the polyatomic ion. A polyatomic ion with a positive charge has more protons than electrons , whereas a polyatomic ion with a negative charge has more electrons than protons.
Estimate the size of the radius of the polyatomic ion. The methods of polyatomic ions consist of how they will interact with other atoms or molecules, as well as how tightly they hold their own electrons. The higher the quantity of positive charge on a polyatomic ion, the smaller the ionic radius will be. Such a polyatomic ion will be more likely to react strongly with another atom or molecule.
Learn the names of the polyatomic ions. Memorizing the methods of polyatomic ions also consists of knowing the names of them. Some of the most common polyatomic ions are the hydroxide ion, cyanide ion, ammonium ion, carbonate, chlorate, chromate, dichromate, hydrogen phosphate, hydrogen carbonate, hydrogen sulfate, nitrate, nitrite, permanganate, phosphate, sulfate, sulfite, and thiocyanate.
Make a chart that consists of the name of the polyatomic ion with its chemical formula next to it. Practice writing the chemical formula, while only reading the name of the polyatomic ion. Also, practice writing the name of the polyatomic ion while only looking at the chemical formula. This mechanism will help you to memorize the methods of the polyatomic ions.