Polyatomic Ions

POLYATOMIC IONS Julie’s Study Guides http://guidesbyjulie.blogspot.com/ 1  -1 ions Acetate

CH3COO-

Bromate

BrO3-

Chlorate

ClO3-

Chlorite

ClO2-

Cyanide

CN-

Dihydrogen phosphate

H2PO4-

Hydrogen carbonate (bicarbonate) Hydrogen sulfate

HCO3-

Hydroxide

OH-

Hypochlorite

ClO-

Nitrate

NO3-

Nitrite

NO2-

Perchlorate

ClO4-

Permanganate

MnO4-

HSO4-

-2 ions Carbonate

CO3-2

Chromate

CrO4-2

Dichromate

Cr2O7-2

Hydrogen phosphate

HPO4-2

Oxalate

C2O4-2

Peroxide

O2-2

Sulfate

SO4-2

Sulfite

SO3-2 -3 ions

Arsenate

AsO4-3

Phosphate

PO4-3

Positive ions Ammonium

NH4+

POLYATOMIC IONS Julie’s Study Guides http://guidesbyjulie.blogspot.com/ 2  Dimercury

Hg2+2 Oxyanions (example)

Hypochlorite

ClO-

Chlorite

ClO2-

Chlorate

ClO3-

Perchlorate

ClO4-

Some tips, in case you are having problems memorizing these, follow: ™ Try to connect the charges and bonding to the periodic table. For example, arsenic and phosphate belong to the same group and therefore bond with the same number of oxygen atoms (producing compounds with the same charge). ™ Remember, sulfur is the only one on the list with an “-ate” ion with four oxygen atoms and an “-ite” ion with three oxygen atoms. ™ For the oxyanions chart, remember your prefixes. “Hypo” means less/fewer, “(Hy-)per” means more. See also: page 858 in the Pre-IB Chemistry book (Modern Chemistry) or page 107 in the AP Chemistry book (Chemistry and Chemical Reactivity) or page 158 in the Barron's AP Chemistry guide.