Chemical Nomenclature


Before doing Chemistry, you should know the language. Instead of memorizing all the names of all the chemicals, like polyatomic ions, there’s a few tricks worth knowing. Here I’ll draw out methods for naming covalent compounds, ionic compounds, acids and a few simple organic compounds.

  • Binary Compounds
    • Covalent Compounds (2 non metals)
      • Molecular formula -> Name
        • Only use a prefix on the first element if the first element has more than one atom! (with the exception of H)
        • Name the first element
        • Use a prefix for the SECOND element
        • Name the second element, but add suffix “-ide”
        • Examples:
          • PCl3 = phosphorus trichloride
          • N2O = dinitrogen monoxide
          • N2O5 = dinitrigen pentoxide
      • And this can be used in reverse to determine the formula from the name.
    • Ionic compounds
      • Metals with a single charge
        • Alkali Metals (1+ charge)
        • Alkaline Earth Metals (2+ charge)
        • Aluminum ion (3+ charge), Silver ion (1+ charge), Zinc ion (2+ charge), and Cadmium ion (2+ charge)
          • Name the metal
          • Name the nonmetal but change the suffix to “-ide”
          • Examples:
            • NaCl = sodium chloride
            • BaBr2 = barium bromide
            • AgCl = silver chloride
          • The metal and non metal chemical formula can be determined from the name when taking into account charges. Just make sure to give subscripts where necessary to make the overall charge zero.
      • Metals with multiple charges
        • Transitional metals (besides Zn, Ag and Cd) form more than one charge state. The non-transition metals that also have these multiple charges are lead and tin.
        • These charges range from 1+ to 4+. You can deduce the charge of these metals when paired with an anion (whose charge you know)
          • Molecular Formula -> Name (classical system)
            • Determine the charge of the metal
              • Look at the anion’s charge
              • Use subscripts to make out the charge to make a balanced compound
            • Name the metal using the classical system
              • Metals of lower charge will have the suffix “-ous”
              • Metals of a higher charge will have the suffix “-ic”
            • Name the non metal and add “-ide”
            • Examples:
              • FeO = Ferrous oxide
                • O has a charge of 2-, therefore iron has a charge of 2+, this is a smaller charge so we call it ferrous
          • Molecular Formula -> Name (stock system)
            • Determine the charge on the metal
              • look at the charge on the anion
              • take subscripts into account
            • Use the name of the metal plus a roman numeral in parenthesis indicating the charge of the metal.
            • name the non-metal adding “-ide”
  • Polyatomic Ionic compounds
    • A polyatomic ion is a covalently bonded group of atoms that either gain or loses electrons to form an ion. While the majority of the common polyatomic ions are anions, there are two cations (NH4+ and Hg2 ^2+)Image result for list of polyatomic ions
    • Chemical Formula -> Name
      • Locate the common groups of polyatomic ions in the formula
      • Name the polyatomic cation or name the metal (using methods above)
      • Name the polyatomic anion or name the monatomic anion as before using the rules for binary compounds.
      • Examples:
        • (NH4)2SO4 = Looking at the table, there are two polyatomic ions in this formula. Ammonium acts as the cation while sulfate acts as the anion. The compound is called ammonium sulfate.

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