NOMENCLATURE

Elements with two less
oxygens than the “ate” ions use the prefix hypo then the root and end in ite. Hypo-root-ite.
Name Symbol
Hypobromite BrO1-
Hypochlorite ClO1-
Hyponitrite N2O22-
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Hyposulfite SO22-
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HypophosphitePO23- / Elements with one less oxygen than the “ate” ions use the root and end in ite.
Root-ite.

Name Symbol

Bromite BrO21-
Chlorite ClO21-
Nitrite NO21-
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SulfiteSO32-
Arsenite AsO33-
Phosphite PO33- / These are the Root-ate ions from which the other ion names can be derived.
Memorize this list.
Name Symbol
Bromate BrO31-
Chlorate ClO31-
NitrateNO31-
CarbonateCO32-
Chromate CrO42-
Manganate MnO42-
Sulfate SO42-
Arsenate AsO43-
PhosphatePO43- / Elements with one more oxygen than the “ate” ions use the prefix per then the root and end in ate.
Per-root-ate.
Name Symbol
Perbromate BrO41-
Perchlorate ClO41-
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Permanganate MnO41-
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Naming monatomic anion acids
When naming acids you must pay
particular attention to the ion forming the acid. First acids formed from monatomic anions.
Hydro-root-ic-acid
Ion Formula Name
Cl1- HCl Hydrochloric acid
S2- H2S Hydrosulfuric acid
F1- HF Hydrofluric acid
Br1- HBr Hydrobromic acid / Naming polyatomic anion acids
Acids that are formed from ions that end in ite are named by replacing the ite with ous acid.
Hypo-root-ite ==> Hypo-root-ous acid
Root-ite ==> Root-ous acid
Acids that are formed from ions that end in ate are named by replacing the ate with ic acid.
Per-root-ate ==> Per-root-ic acid
Root-ate ==> Root-ic acid
Ion Formula Name .
ClO1- HClO Hypochlorous acid
ClO21- HClO2 Chlorous acid
ClO31- HClO3 Chloric acid
ClO41- HClO4 Perchloric acid / Positive ions (cation) simply give the
name of the metal. If the metal exhibits more than one charge, you must give the charge in roman numerals.
Symbol Name Old name
Ca2+ Calcium
Cr3+ Chromium (III)Chromic
Cu1+ Copper (I) Cuprous
Cu2+ Copper (II) Cupric
Fe2+ Iron (II) Ferrous
Fe3+ Iron (III) Ferric
Na+ Sodium
Pb2+ Lead (II) Plumbus
Pb4+Lead (IV)Plumbic
Monatomic negative ions (anions) use the root of the element and end in ide. Root-ide
Element Ion Symbol Fluorine Fluoride F1-
Chlorine Chloride Cl1-
Bromine Bromide Br1-
Iodine Iodide I1-
Oxygen Oxide O2- **
Sulfur Sulfide S2-
Nitrogen Nitride N3- **
Phosphorous Phosphide P3-
Carbon Carbide C4- ** / Hydrogen Associated Ions. When the 2- or 3- charged ions at the top form ions with one or two associated hydrogens, use the prefix hydrogen (di for 2 hydrogens)

Name Symbol Old Name

Hydrogen sulfate HSO41-Bisulfate
Hydrogen carbonate HCO31-Bicarbonate
Hydrogen phosphateHPO42-
Dihydrogen phosphate H2PO41- / Other common ions that are not regular or follow old nomenclature.
Name Ion .
Acetate C2H3O21-
Ammonium NH4+
Hydroxide OH1-
Oxalate C2O42-
Cyanide CN1-
Chromate CrO42-
Dichromate Cr2O72-
Thiosulfate S2O32-
Naming molecular compounds, you must use prefixes to indicate the number of each element present. One exception is when there is only one of the first element, and the prefix is omitted.
Prefixes Meaning
Mono1
Di 2
Tri 3
Tetra 4
Penta 5
Hexa6
Hepta7
Octa8
When the element begins in a vowel, you omit the ‘a’ at
the end of the prefix.
Formula Name
NO2 Nitrogen dioxide
N2O4 Dinitrogen tetroxide
SO3 Sulfur trioxide
P3O4 Triphosphorous tetroxide