Nomenclature of Binary Compounds and Polyatomic Ions PDF

Nomenclature The naming of compounds Nomenclature Basics  Nomenclature is the system that scientists use to name compounds.  Some compounds go by their common names such as water and ammonia.  Most follow naming rules depend on which type of compound the substance is. ...

Nomenclature The naming of compounds Nomenclature Basics  Nomenclature is the system that scientists use to name compounds.  Some compounds go by their common names such as water and ammonia.  Most follow naming rules depend on which type of compound the substance is.  Today we will focus on binary compounds – compounds made up of two different elements only.  You should be able to name the compound from the chemical formula and write the chemical formula from the name.  Type I Binary Ionic Compounds  These compounds are formed from metals that can produce only one type of cation and an anion.  These cations usually come from Groups 1, 2, and 13  Rules:  The cation is always named first and the anion second  A simple cation takes the name of the element  A simple anion is named by changing the end of the element name to -ide  Type I Binary Ionic Compounds Sodium chloride = NaCl Magnesium chloride = MgCl2 Potassium oxide = K2O AlCl3 = aluminum chloride Li2S = lithium sulfide Ca3N2 = calcium nitride  Type II Binary Ionic Compounds  Composed from metals that can form more than one type of cation. These are usually the transition metals.  Rules  The cation is named by using the element name followed by a number in roman numerals (in parenthesis) indicating the charge of the ion.  The anion name changes to end in –ide.  Type II Binary Ionic Compounds Common Type II Ions: Fe3+ iron (III) Sn4+ tin (IV) Fe2+ iron (II) Sn2+ tin (II) Cu2+ copper (II) Pb4+ lead (IV) Cu+ copper (I) Pb2+ lead (II) Co3+ cobalt (III) Hg2+ mercury (II) Co2+ cobalt (II) Hg22+ mercury (I)  Type II Binary Ionic Compounds Copper (II) bromide = CuBr2 Copper (I) bromide = CuBr FeI3 = iron (III) iodide Co2O3 = cobalt (III) oxide Ion Chart Type III Binary Compounds  These compounds are composed of two nonmetals.  These are primarily held by covalent bonds forming molecules.  Rules:  The first element uses its full name  The second element is named as if it were an anion (ending changes to –ide)  Prefixes are used to denote the numbers of atoms present.  The prefix mono- is not used with the first element Type III Binary Compounds Prefixes: 1 mono- 6 hexa- 2 di- 7 hepta- 3 tri- 8 octa- 4 tetra- 9 nona- 5 penta- 10 deca- Type III Binary Compounds  Sometimes a letter is dropped when a prefix is added so it sounds better  Examples:  CO is carbon monoxide (not carbon monooxide)  N2O4 is dinitrogen tetroxide (not dinitrogen tetraoxide) Type III Binary Compounds N3O5 = trinitrogen pentoxide SI6 = sulfur hexaiodide Dinitrogen tetroxide = N2O4 Sulfur trioxide = SO3  Polyatomic Ions A polyatomic ion is an ion that is composed of more than one atom bonded together. The only way to know the polyatomic ions is to memorize them. They are named the same way the Type I binary ionic compounds are named except you never change the name of the polyatomic ion. When you have two or more of the same polyatomic ion, we put parenthesis around the ion and put the subscript on the outside of the parenthesis.  Naming with Polyatomic Ions Sodium carbonate = Na2CO3 Magnesium hydroxide = Mg(OH)2 Ammonium sulfate = (NH4)2SO4 NH4OH = ammonium hydroxide Ba(NO3)2 = barium nitrate Ca(OH)2 = calcium hydroxide Al(NO2)3 = aluminum nitrite