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Chemistry Nomenclature & Ions

Jun 16, 2025

Overview

This lecture covers key nomenclature rules in inorganic and organic chemistry, including common ions, formula writing, naming conventions, and important prefixes.

Common Polyatomic Ions & Formulas

  • Ammonium: NH₄⁺
  • Carbonate: CO₃²⁻
  • Hydrogen carbonate (bicarbonate): HCO₃⁻
  • Phosphate: PO₄³⁻
  • Hydrogen phosphate: HPO₄²⁻
  • Dihydrogen phosphate: H₂PO₄⁻
  • Nitrate: NO₃⁻
  • Sulfate: SO₄²⁻
  • Hydrogen sulfate (bisulfate): HSO₄⁻
  • Chromate: CrO₄²⁻
  • Dichromate: Cr₂O₇²⁻
  • Permanganate: MnO₄⁻
  • Oxalate: C₂O₄²⁻
  • Hydroxide: OH⁻
  • Peroxide: O₂²⁻
  • Cyanide: CN⁻
  • Acetate: C₂H₃O₂⁻ or CH₃COO⁻
  • Acetic acid: CH₃COOH or HC₂H₃O₂

Common Ion Charges

  • Zinc: Zn²⁺
  • Silver: Ag⁺
  • Nickel: Ni²⁺
  • Cadmium: Cd²⁺
  • Group 1A metals: +1
  • Group 2A metals: +2
  • Group 3A metals (Al, Ga): +3
  • Group 5A nonmetals: -3
  • Group 6A nonmetals: -2
  • Group 7A nonmetals: -1

Numerical Prefixes

  • 1: mono-
  • 2: di-
  • 3: tri-
  • 4: tetra-
  • 5: penta-
  • 6: hexa-
  • 7: hepta-
  • 8: octa-
  • 9: nona-
  • 10: deca-

Compound Naming Conventions

  • Binary ionic: Name cation first, then anion root + "-ide".
  • Binary molecular: Use Greek prefixes; second element ends in "-ide".
  • Binary acid: "hydro-" + root + "-ic acid" (e.g., HBr = hydrobromic acid).
  • Oxoacid: "-ate" → "-ic acid," "-ite" → "-ous acid"; retain "per-" or "hypo-" if present.
  • Hydrate: Name ionic compound, then prefix + "hydrate" (e.g., pentahydrate).

Simple Organic Formulas

  • Methane: CH₄
  • Ethane: C₂H₆
  • Propane: C₃H₈
  • Methanol: CH₃OH
  • Ethanol: C₂H₅OH
  • Methylamine: CH₃NH₂
  • Dimethylamine: (CH₃)₂NH
  • Ethylamine: C₂H₅NH₂
  • Formic acid (methanoic acid): HCOOH

Key Terms & Definitions

  • Polyatomic ion — Ion composed of multiple atoms bonded together with an overall charge.
  • Binary ionic compound — Compound of a metal cation and nonmetal anion.
  • Binary molecular compound — Compound of two nonmetals using Greek prefixes.
  • Oxoacid — Acid containing hydrogen, oxygen, and another element.
  • Hydrate — Salt with water molecules attached in its crystal structure.

Action Items / Next Steps

  • Review and memorize common ion formulas and their charges.
  • Practice naming compounds using the provided rules.
  • Complete any assigned readings or practice problems on nomenclature.