AP Chemistry Polyatomic Ions flashcards
This deck is the standard polyatomic ion memorization set: each card gives an ion name and asks for its formula and charge. It covers the common oxyanions (nitrate and nitrite, sulfate and sulfite, phosphate and phosphite, carbonate, chromate and dichromate, permanganate), the chlorine oxyanion series from hypochlorite through perchlorate, the hydrogen-bearing anions such as bicarbonate and hydrogen phosphate, the two common polyatomic cations, and the naming patterns that connect them.
AP Chemistry never asks you to name an ion for its own sake, but it assumes the formulas everywhere: writing balanced net ionic equations, assigning oxidation numbers, computing molar masses in stoichiometry and applying solubility rules all break down if the charge is wrong. Charge is the part students lose points on most often, so every card states it explicitly rather than leaving it implied by the formula.
The deck
How to study this deck
- Learn the -ate ion of each family first (nitrate, sulfate, chlorate, phosphate), then derive the rest: the -ite form has one fewer oxygen, hypo- has one fewer than -ite, per- has one more than -ate, and the charge never changes across the series.
- Drill name-to-formula and formula-to-name in both directions. Free response hands you a name and expects a correct formula, multiple choice usually does the reverse, and knowing one direction does not automatically give you the other.
- Group the ions by charge rather than alphabetically — all the 1- ions, then the 2- ions, then phosphate and phosphite at 3-. Charge is what you actually need when balancing a formula unit, and grouping this way makes the outliers stand out.