Module 5

Learning Objectives

• Derive names for common types of inorganic compounds using a systematic approach.

Nomenclature Overview

• Nomenclature: A set of rules for naming compounds is crucial in science.

• Focus on simple ionic and molecular compounds like NaCl, CaCO3, and N2O4.

• Binary compounds contain only two elements.

• Consider naming ionic compounds with polyatomic ions and acids in future studies.

• Focus on inorganic compounds (with elements other than carbon).

Ionic Compounds

• Important questions for naming compounds:

  • Is the compound ionic or molecular?

  • Does the metal form ions of fixed or variable charge?

  • Are ions monatomic or polyatomic?

• Binary Compounds: Name consists of cation (metal name) and anion (nonmetal with –ide suffix).

Examples of Monatomic Ionic Compounds

• NaCl: sodium chloride

• Na2O: sodium oxide

• KBr: potassium bromide

• CdS: cadmium sulfide

• CaI2: calcium iodide

• Mg3N2: magnesium nitride

• CsF: cesium fluoride

• Ca3P2: calcium phosphide

• LiCl: lithium chloride

• Al4C3: aluminum carbide

Everyday Ionic Compounds

• Ionic compounds encountered daily:

  • Check labels for familiar ionic compounds.

Examples of Polyatomic Ionic Compounds

• KC2H3O2: potassium acetate

• NH4Cl: ammonium chloride

• NaHCO3: sodium bicarbonate

• CaSO4: calcium sulfate

• Al2(CO3)3: aluminum carbonate

• Mg3(PO4)2: magnesium phosphate

Uses of Common Ionic Compounds

• NaCl: ordinary table salt

• KI: added to iodized salt for thyroid health

• NaF: ingredient in toothpaste

• NaHCO3: baking soda; used in cooking and as antacid

• Na2CO3: washing soda; used in cleaning agents

• NaOCl: active ingredient in household bleach

• CaCO3: ingredient in antacids

• Mg(OH)2: ingredient in antacids

• Al(OH)3: ingredient in antacids

Compounds with Variable Charge Ions

• Transition and some main group metals can form cations with different charges.

• Names include metal charge in Roman numerals in parentheses (e.g., iron(II) chloride).

Examples of Variable Charge Ionic Compounds

• FeCl2: iron(II) chloride

• FeCl3: iron(III) chloride

• Hg2O: mercury(I) oxide

• HgO: mercury(II) oxide

• SnF2: tin(II) fluoride

• SnF4: tin(IV) fluoride

Nomenclature Trends

• Previous naming conventions included suffixes –ic and –ous for metals with higher or lower charges, respectively.

• Example: Ferric chloride for FeCl3, Ferrous chloride for FeCl2 (less common now).

• Common usage still exists in industry (e.g., stannous fluoride).

Ionic Hydrates

• Ionic compounds with associated water molecules are termed hydrates.

• Naming adds a term to indicate the number of water molecules using Greek prefixes.

• Example: copper(II) sulfate pentahydrate (CuSO4∙5H2O).

Naming Ionic Compounds Example

1. Name the compound:

• (a) Fe2S3: iron(III) sulfide

• (b) CuSe: copper(II) selenide

• (c) GaN: gallium(III) nitride

• (d) MgSO4∙7H2O: magnesium sulfate heptahydrate

• (e) Ti2(SO4)3: titanium(III) sulfate

Nomenclature Prefixes for Covalent Compounds

Naming Covalent Compounds

• Ratios in molecular compounds must be explicitly identified using prefixes.

• Example: CO is carbon monoxide; CO2 is carbon dioxide.

Common Molecular Compounds Examples

• SO2: sulfur dioxide

• SO3: sulfur trioxide

• NO2: nitrogen dioxide

• BCl3: boron trichloride

Naming Simple Acids

• Binary acids are named by modifying the nonmetal's name.

  1. Prefix "hydro-" for hydrogen.

  2. Change nonmetal’s suffix to –ic.

  3. Add "acid".

• Example: HCl (hydrogen chloride) becomes hydrochloric acid.

Examples of Binary Acids

• HF(g) = hydrogen fluoride; HF(aq) = hydrofluoric acid

• HCl(g) = hydrogen chloride; HCl(aq) = hydrochloric acid

• H2S(g) = hydrogen sulfide; H2S(aq) = hydrosulfuric acid

Oxyacids Naming

• Oxyacids contain hydrogen and oxygen with another element.

• Name by omitting "hydrogen" and changing anion names.

  1. Replace –ate with –ic.

  2. Replace –ite with –ous.

  3. Add "acid."

• Example: H2CO3 is carbonic acid (not "hydrogen carbonate").

Common Oxyacids Examples