Naming Compounds

Practice writing formulas from names and names from formulas — elements, polyatomic ions, binary covalent, binary acids, oxyacids, and ionic compounds (including transition metals).

Naming rules — quick reference
Elements (single elements) Name corresponds directly to the chemical symbol on the periodic table. Example: Fe → iron.
Polyatomic ions (charged molecular groups) Covalently bonded atoms with an overall charge. Subscripts show atomic composition, superscripts show net charge. Example: SO₄²⁻ → sulfate.
Binary covalent (two nonmetals) Prefixes give the count of each element: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-. The first element only gets a prefix if there's more than one atom (never "mono-"). Drop a vowel-vowel clash: monoxide, not "monooxide." Second element ends in -ide. Example: N₂O₅ → dinitrogen pentoxide.
Binary acids (H + one nonmetal, aqueous) hydro- + root + -ic acid. Example: HBr → hydrobromic acid.
Oxyacids (H + polyatomic ion with oxygen) -ate ion → -ic acid. -ite ion → -ous acid. Example: sulfate → sulfuric acid (H₂SO₄); sulfite → sulfurous acid (H₂SO₃). Per-/hypo- prefixes carry over: perchlorate → perchloric acid, hypochlorite → hypochlorous acid.
Ionic compounds (metal + nonmetal or polyatomic ion) Cation name first, anion second (ends in -ide for simple ions, or keeps its polyatomic name, e.g. sulfate, hydroxide). Transition/multi-charge metals need a roman numeral for the charge, found from the anion's charge: FeCl₃ → iron(III) chloride. No subscripts appear in the name — the roman numeral already tells you the ratio.

Compound types

Practice Mode

Name / Formula
Compound Type
Both

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