Presentation on theme: "Chapter 8. Chemical Nomenclature"— Presentation transcript:
1 Chapter 8. Chemical Nomenclature Chemical nomenclature is the system of names used to distinguish chemical compounds from each other, and the rules needed to devise these names.
2 Chemical Nomenclature Why Bother?How do you speak Al2(SO4)3 ?What system do we use?IUPAC International Union of Pure and Applied Chemistry
3 Chemical Nomenclature Three major categories of compounds:IonicFirst element in formula is a metal.MolecularFirst element in formula is a nonmetal.AcidFirst element in formula is Hydrogen.
4 Naming Ionic Compounds Types of ionic compounds:Binary, contains two elements:NaCl, MgBr2, Fe2O3Ternary, contains three elements; two are in a polyatomic anion:NaNO3, NH4Cl, Cr2(SO4)3
5 Naming Binary Ionic Compounds What is the charge on the metal ion?Fixed: Group 1A, +1; Group 2A, +2Al3+, Ga3+, Zn2+, Cd2+, Ag1+Examples: NaCl, Al2O3, CdSName cation as element, e.g. sodiumName anion with stem of element name, followed by suffix ide, e.g. chloride
6 Naming Binary Ionic Compounds What is the charge on the metal ion?Variable: All other metalsExamples: CuO, FeBr2, Fe2O3Name cation as element, followed by charge in Roman numerals, enclosed by parentheses, e.g. copper(II)Name anion with stem of element name, followed by suffix ide, e.g. oxide
7 Naming Binary Ionic Compounds What is the charge on the metal ion?The compound must be electrically neutral.Use the charge on the anion to figure out the charge on the metal.Examples: FeO, Fe2O3CuCl, CuCl2SnF2, SnF4Hg2Cl2, HgCl2
8 Naming Binary Ionic Compounds An older naming system gives the suffix ic to the ion with the higher charge, and the suf-fix ous to the ion with the lower charge, following the (usually Latin) element stem.FeO ferrous oxide; Fe2O3 ferric oxideCuCl cuprous chloride CuCl2 cupric chlorideSnF2 stannous fluoride SnF4 stannic fluorideHg2Cl2 mercurous chloride HgCl2 mercuric chloride
9 Naming Ternary Ionic Compounds Name metal as you would for a binary, with charge if necessary.Name anion as itself. Know these:CO32- carbonate ClO1- hypochloriteNO31- nitrate ClO31- chloratePO43- phosphate C2H3O21- acetateSO42- sulfate CH3COO1- acetateOH1- hydroxide CN1- cyanide
10 Naming Ternary Ionic Compounds There is one polyatomic cationNH41+, ammoniumName it, then name anion properly
11 Formulas from Names Write symbol for metal ion first, then anion. Use the charges on the ions to determine how many of each ion are present in the formula. Charges must sum to zero.If a polyatomic ion appears more than once in a formula, enclose it in parentheses, followed by a subscript showing the number of times the ion occurs in the compound.
12 Practice Give Name Give Formula CaCl2 Mercurous iodide Mg(NO3)2 Mercury(II) iodideAl2(SO4)3 Silver nitrateFeCl3 Ammonium bromideAgBr Tin(II) hydroxideMnO2 Sodium cyanideNH4NO3 Calcium phosphate
13 Naming Molecular Compounds These are all binary. Since the atoms do not have charges, use Greek numerical prefix-es to indicate the number of each atom in the molecule.Know these:1 mono 4 tetra2 di penta3 tri hexa
14 Naming Molecular Compounds How to name them:1. Prefix for first element in formula, omit if it's "mono"2. Name first element2. Prefix for second element in formula,3. Give stem of second element followed by suffix ide.CO Carbon monoxideCO2 Carbon dioxideN2O Dinitrogen monoxide
15 Naming Molecular Compounds Details and exceptions:If last letter of prefix for number and first letter of element are both vowels, drop the last letter of the prefix:CO carbon monoxideN2O5 dinitrogen pentoxideSome compounds are known only by common names.H2O water NH3 ammonia
16 Formulas from NamesWrite symbol for least electronegative element first, then most electronegative.Use prefixes to determine subscripts in formula.Metalloids are not metals, and their com-pounds are named as molecular com-pounds.
17 Practice Give Name Give Formula NO2 Carbon tetrachloride SO3 Phosphorus trichlorideSiO2 Selenium dibromideTiO2 Dinitrogen tetroxideNO Sulfur dioxideP2O5 Xenon tetrafluorideFe2O3 Diantimony Trioxide
18 Naming Acids Types of acids: Binary, contains two elements: HCl, HBr, H2STernary, contains three elements; two are in a polyatomic ion:HNO3, H2SO4, H3PO4
19 Naming Binary Acids Binary acids are gases as pure compounds. Symbol: HCl or HCl (g)Name: hydrogen + stem of nonmetal followed by suffix -ide.hydrogen chloride
20 Naming Binary AcidsThe compounds become acidic in water solution (aqueous solution); they ionize.HCl + H2O H3O Cl1-H3O1+ is what makes acids acidic.Symbol: HCl (aq)Name: prefix hydro- + stem of nonmetal followed by suffix -ic acid.hydrochloric acid
21 Naming Ternary AcidsNo distinction is made between pure ternary acids and those in aqueous (water) solution.Symbol: H2SO4Name: stem of central atom followed by suffix -ic acid.sulfuric acid
22 Naming Ternary AcidsKnow names of these ternary acids. They are related to "must know" polyatomic anions:H2CO3 HClOHNO3 HClO3H3PO HC2H3O2H2SO4 CH3COOHHOH HCN (aq)
23 Naming Acids and Anions Useful Generalization:If the name of an anion ends in -ide, its aqueous acid is named as hydrostemic acid.If the name of an anion ends in -ate, its acid is named as stemic acid.
24 Practice Give Name Give Formula HBr (aq) Sulfuric acid HNO3 Carbonic acidH2O Hydrogen iodideH2S Hypochlorous acidHF Hydrocyanic acidH3PO4 Acetic acidHI (aq) Chloric acid
25 Naming Mixed SaltsMixed salts are compounds in which Na1+ or K1+ combine with H1+ and an anion with -2 or -3 charge.Symbol: KHSO4Name: metal cation, hydrogen, anionPotassium hydrogen sulfate
26 Naming Mixed SaltsIf the anion has -3 charge (PO43-), three cations are required to form a neutral compound.Symbol: NaH2PO4Name: metal cation, prefix di-hydrogen, anion Sodium dihydrogen phosphateSymbol: K2HPO4Name: prefix di-metal cation, hydrogen, anion Dipotassium hydrogen phosphate
27 More Practice Give Name Give Formula AgNO3 Magnesium sulfate CaS Ferric chlorideNH3 Nitric acidNaHS Lead(IV) sulfateZrO2 Sodium hydrogen carbonateH2SO4 Mercuric bromideAl2O3 Phosphorus trifluoride