Molecular Compounds

Objective: Apply common naming patterns with stated scope.

A simple binary ionic compound usually names the cation first and the anion with an -ide ending: NaCl is sodium chloride. Some metals form multiple ion charges and require a Roman numeral, such as iron(III) chloride for FeCl₃. Binary molecular compounds of nonmetals can use prefixes to indicate atom counts, such as carbon dioxide for CO₂ and dinitrogen tetroxide for N₂O₄. Naming conventions have exceptions and common names; the formula and charge model must be considered. Polyatomic ions such as nitrate retain group names in many compounds. A Roman numeral gives metal ion charge, not the number of metal atoms.

Objective: Apply molecular compounds to calculations, evidence, and specified situations.

Binary molecular names use prefixes to state the number of atoms of each element. The first element usually omits mono-; the second uses an -ide ending with a prefix. Some common vowel contractions produce monoxide and tetroxide. These rules apply to the stated binary molecular compounds, not every chemical substance; water and many acids have established naming conventions. Name the stated formula without changing subscripts to satisfy an ionic charge rule.