POLYATOMIC IONS
(MEMORIZE!! MEMORIZE!!! DO IT!! DO IT NOW!!!)
Assignment: Create a set of note cards to help you memorize the
polyatomic ions. Each note card should have the chemical formula (with
charge) on one side and the IUPAC name on the other side.
For example:
C2H3O2-
Acetate
(front)
(back)
Formula (charge)
C2H3O2NH4+
BO33BrO3BrO2CO32ClO3ClO2CrO42CNCr2O72HCO3HSO4OHClOIO3IO2NO3NO2ClO4MnO4PO43PO33SO42SO32-
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Name
Acetate
Ammonium
Borate
Bromate
Bromite
Carbonate
Chlorate
Chlorite
Chromate
Cyanide
Dichromate
HydrogenCarbonate
HydrogenSulfate
Hydroxide
Hypochlorite
Iodate
Iodite
Nitrate
Nitrite
Perchlorate
Permanganate
Phosphate
Phosphite
Sulfate
Sulfite
Mnemonic Aids for the Polyatomic Ions
The sentence below can be used to remember some of the polyatomic ions
Nick the Camel ate a Clam and Crepes for Supper in Phoenix
The number of consonant represent the number of oxygen and the number of vowels
represent the charge.
Nick - N with 3 consonants and 1 vowel therefore NO3-1 (nitrate)
Camel - C with 3 consonants and 2 vowels, therefore CO3-2 (carbonate)
Clam - Cl with 3 consonants and 2 vowels, therefore ClO3-1 (chlorate)
Crepes- CrO4-2 Cr with 4 consonants and 2 vowels, therefore CrO4-2(chromate)
Supper - S with 4 consonants and 2 vowels, therefore SO4-2 (sulfate)
Phoenix - P with 4 consonants and 3 vowels, therefore PO4-3 (phosphate)
*To find bromate and iodate replace the Cl with Br and I since they are all halogens.
1. -ite is one less oxygen, so…
Nitrate NO3-1 becomes NO2-1 or nitrite
Chlorate ClO3-1 becomes ClO2-1 or chlorite
Sulfate SO4-2 becomes SO3-2 or sulfite
Phosphate PO4-3 becomes PO3-3 or phosphite
2. The addition of Hydrogen adds +1 to the charge so..
Carbonate CO32-with hydrogen becomes HCO3-1 or hydrogen carbonate.
Sulfate SO4-2 with hydrogen becomes HSO4-1 or hydrogen sulfate.
3. Learn the hypochlorite  chlorite  chlorate  perchlorate series, and you also
know the series containing iodite/iodate as well as bromite/bromate.
a. The relationship between the “ite” and “ate” ion is predictable, as always. Learn
one and you know the other.
b. The prefix “hypo” means “under” or “too little” (think “hypodermic”, “hypothermic”
or “hypoglycemia”)
i. Hypochlorite is “under” chlorite, meaning it has one less oxygen
c. The prefix “hyper” means “above” or “too much” (think “hyperkinetic”)
i. the prefix “per” is derived from “hyper” so perchlorate (hyperchlorate) has one
more oxygen than chlorate.
d. Notice how this sequence increases in oxygen while retaining the same charge:
ClO-1

Hypochlorite
ClO21chlorite

ClO31chlorate

ClO41perchlorate