CHEM 1305: Introductory Chemistry Naming Inorganic Compounds From Chapter 6 Textbook Introductory Chemistry: Concepts and Critical Thinking Seventh Edition by Charles H. Corwin
Language of Chemistry By the 1700s, more than 10,000 compounds were discovered All compounds shown here contain manganese How should they be named? In 1787, Antoine Lavoisier developed a systematic method of naming substances, based on what they were composed of 2
Classification of Compounds In 1940, the International Union of Pure and Applied Chemistry (IUPAC) released a set of comprehensive rules on the nomenclature of inorganic compounds referred to as IUPAC nomenclature An inorganic compound does not contain carbon (with the exception of CO 2, CS 2, and compounds containing CO 3 2- and HCO 3- ) Inorganic compounds can be placed into 5 common categories: binary ionic compound, ternary ionic compound, binary molecular compound, binary acid, and ternary oxyacid An aqueous solution is produced when a compound dissolved in water typically indicated by the symbol (aq) 3
Classification of Inorganic Compounds 2 elements: metal, nonmetal 3 elements: metal, nonmetal, other 2 elements: both nonmetals 2 elements (aq): hydrogen, nonmetal 3 elements (aq): hydrogen, nonmetal, oxygen 4
Classifying Compounds and Acids Classify each of the following as a binary ionic compound, ternary ionic compound, binary molecular compound, binary acid, or ternary oxyacid: calcium oxide, CaO silver chromate, Ag 2 CrO 4 carbonic acid, H 2 CO 3 (aq) sulfur dioxide, SO 2 hydrofluoric acid, HF(aq) carbon disulfide, CS 2 magnesium iodide, MgI 2 hydrochloric acid, HCl(aq) lithium dichromate, Li 2 Cr 2 O 7 nitric acid, HNO 3 (aq) binary ionic compound ternary ionic compound ternary oxyacid binary molecular compound binary acid binary molecular compound binary ionic compound binary acid ternary ionic compound ternary oxyacid 5
Classifying Ions Ions are also named systematically, according to IUPAC nomenclature A positive ion is a cation and a negative ion is an anion A single, charged atom is a monoatomic ion A group of atoms, having an overall charge is called a polyatomic ion 6
Classifying Cations and Anions Classify each of the following as a monoatomic cation, monoatomic anion, polyatomic cation or polyatomic anion barium ion, Ba 2+ monoatomic cation chloride ion, Cl - monoatomic anion ammonium ion, NH + 4 polyatomic cation carbonate ion, CO 2-3 polyatomic anion hydronium ion, H 3 O + polyatomic cation sulfide ion, S 2- monoatomic anion permanganate ion, MnO - 4 polyatomic anion stannous ion, Sn 2+ monoatomic cation 7
Naming Metal Ions Metal atoms can lose valence electrons and become cations Metal cations are named for the parent metal followed by the word ion Na + is sodium ion; Mg 2+ is magnesium ion; Al 3+ is aluminum ion Main-group metals usually form one type of cation, except Sn and Pb Transition metals often form more than one type of cation Iron can form both Fe 2+ and Fe 3+ To name cations of metals which can have more than one charge, it is necessary to specify the charge IUPAC recommends to name the parent metal, followed by its charge (in Roman numerals), followed by the word ion Fe 2+ is named iron(ii) ion and Fe 3+ is named iron(iii) ion 8
Naming Nonmetal Ions Nonmetal atoms can gain valence electrons and become anions In the IUPAC method, nonmetal ions are named by using the nonmetal stem plus the suffix -ide and the word ion Cl - is chloride ion; S 2- is sulfide ion; P 3- is phosphide ion 9
Predicting Formulas of Monoatomic Ions As discussed in Chapter 5, the charge of an ion can be predicted based on the group number of the element Transition metals are an exception most lose their two s electrons, but others have additional charges which are unpredictable 10
Names and Formulas of Monoatomic Ions Provide a formula for the following monoatomic ions barium ion Ba 2+ cobalt(ii) ion Co 2+ fluoride ion F - oxide ion O 2- iron(iii) ion Fe 3+ Provide a systematic name for the following monoatomic ions Al 3+ Co 3+ Br - N 3- H + aluminum ion cobalt(iii) ion (or cobaltic ion) bromide ion nitride ion hydrogen ion 11
Polyatomic Ions Polyatomic anions usually contain one or more elements combined with oxygen termed an oxyanion 12
Names and Formulas of Polyatomic Ions Provide a systematic name for each of the following: CO 2-3 CrO 2-4 ClO - 2 HSO - 4 OH - carbonate ion chromate ion chlorite ion hydrogen sulfate ion hydroxide ion Provide the formula for each of the following: acetate ion C 2 H 3 O 2 - perchlorate ion ClO 4 - dichromate ion Cr 2 O 7 2- hydrogen carbonate ion HCO 3 - ammonium ion NH 4 + 13
Writing Chemical Formulas An ionic compound is composed of both positive and negative ions A formula unit is the simplest representative particle of an ionic compound, it is neutral total + charge must equal total - charge Sodium chloride contains Na + and Cl - ; formula is NaCl Calcium chloride contains Ca 2+ and Cl - ; formula is CaCl 2 Aluminum chloride contains Al 3+ and Cl - ; formula is AlCl 3 The same applies for polyatomic ions Compound with K + and SO 4 2- ; formula is K 2 SO 4 Compound with Mg 2+ and SO 4 2- ; formula is MgSO 4 Parentheses are needed to indicate multiple number of polyatomic ions Compound with NH 4+ and SO 4 2- ; formula is (NH 4 ) 2 SO 4 14
Writing Chemical Formulas Write the chemical formula for each of the following compounds: copper(i) oxide, Cu + and O 2- Cu 2 O cobalt(iii) oxide, Co 3+ and O 2- Co 2 O 3 iron(ii) sulfide, Fe 2+ and S 2- FeS mercury(i) fluoride, Hg 2+ 2 and F - Hg 2 F 2 lead(iv) oxide, Pb 4+ and O 2- PbO 2 calcium carbonate, Ca 2+ and CO 2-3 CaCO 3 calcium hydroxide, Ca 2+ and OH - Ca(OH) 2 calcium phosphate, Ca 2+ and PO 3-4 Ca 3 (PO 4 ) 2 copper(ii) permanganate, Cu 2+ and MnO - 4 Cu(MnO 4 ) 2 iron(iii) carbonate, Fe 3+ and CO 2-3 Fe 2 (CO 3 ) 3 potassium dichromate, K + and Cr 2 O 2-7 K 2 Cr 2 O 7 15
Binary Ionic Compounds Overall, an ionic compound has a charge of zero, even though it contains charged ions To name ionic compounds correctly, the charge must first be determined For example, what is charge of Fe in Fe 2 O 3? Oxide ion is always O 2- : therefore, 3 (-2) = -6 Total charge from Fe should be +6: 2 (c) = +6 c = +3 (Fe 3+ ) Metal cation is named first, and then monoatomic anion with -ide suffix Fe 2 O 3 is named iron(iii) oxide Remember that formulas of compounds can be predicted based on the formula of a similar compound in the same periodic group (LiCl, NaCl, KCl); (BaCl 2, MgCl 2, CaCl 2, SrCl 2 ) 16
Binary Ionic Compounds Determine the charge for each transition metal: Cu 3 P Cu + CoN Co 3+ Name the following compounds: ZnO zinc oxide SnF 2 tin(ii) fluoride Mn 3 P 2 manganese(ii) phosphide Fe 2 S 3 iron(iii) sulfide Provide the formula for the following: lithium fluoride mercury(ii) oxide LiF HgO Given that aluminum oxide is Al 2 O 3, write formulas for: gallium oxide Ga 2 O 3 aluminum sulfide Al 2 S 3 Fe 2 S pyrite or fool s gold 17
Ternary Ionic Compounds Name ternary ionic compounds similarly to binary ionic compounds, but suffix on anion usually ends with -ate or -ite First, determine the charge of each ion For example, what is charge of Fe in Fe 3 (PO 4 ) 2? Phosphate ion is PO 4 3- : 2 (-3) = -6 Total charge from Fe should be +6: 3 (c) = +6 c = +2 (Fe 2+ ) Metal cation is named first, followed by name of anion (memorize) Fe 3 (PO 4 ) 2 is named iron(ii) phosphate Remember that formulas of compounds can be predicted based on the formula of a similar compound in the same periodic group (LiNO 3, NaNO 3, KNO 3 ); (Ba 3 (PO 4 ) 2, Mg 3 (PO 4 ) 2, Ca 3 (PO 4 ) 2, Sr 3 (PO 4 ) 2 ) 18
Ternary Ionic Compounds Determine the charge for each transition metal: Hg(OH) 2 Hg 2+ Co(ClO 3 ) 3 Co 3+ Name the following compounds: KMnO 4 potassium permanganate Hg(NO 3 ) 2 mercury(ii) nitrate BaCrO 4 barium chromate Cu(NO 2 ) 2 copper(ii) nitrite Provide the formula for the following: nickel(ii) acetate Ni(C 2 H 3 O 2 ) 2 mercury(i) nitrite Hg 2 (NO 2 ) 2 Calcium carbonate is CaCO 3, write formulas for: radium carbonate Ra 2 CO 3 calcium silicate Ca 2 SiO 3 KMnO 4 multiple uses 19
Binary Molecular Compounds The simplest representative particle in a binary molecular compound is a molecule generally, the more metallic element is written second in the chemical formula: C, P, N, H, S, I, Br, Cl, O, F (CH 4, NH 3, HBr) Name the first element, followed by the second with -ide suffix The number of atoms of each element should be indicated using the following Greek prefixes, mono- used only when necessary, CO carbon monoxide 20
Binary Molecular Compounds Name the following compounds: IF 6 Br 3 O 8 Cl 2 O 5 P 4 S 10 PH 3 Provide a formula for each of the following: tetraphosphorus trisulfide P 4 S 3 tetraiodine nonaoxide I 4 O 9 diphosphorus tetraiodide P 2 I 4 iodine hexafluoride tribromine octaoxide dichlorine pentaoxide tetraphosphorus decasulfide phosphorus trihydride SO 2 used as preservative sulfur hexafluoride SF 6 dihydrogen oxide H 2 O www.redorbit.com 21
Binary Acids and Ternary Oxyacids A binary acid chemical formula always begins with H, followed by a nonmetal, and the symbol (aq) A ternary oxyacid chemical formula always begins with H, followed by an oxyanion, and the symbol (aq) ACID IUPAC NAME ACID IUPAC NAME HF(aq) hydrofluoric acid HBr(aq) hydrobromic acid HCl(aq) hydrochloric acid HI(aq) hydroiodic acid HMnO 4 (aq) permanganic acid H 3 PO 4 (aq) phosphoric acid H 2 CrO 4 (aq) chromic acid HClO(aq) hypochlorous acid H 2 Cr 2 O 7 (aq) dichromic acid HClO 2 (aq) chlorous acid HC 2 H 3 O 2 (aq) acetic acid HClO 3 (aq) chloric acid H 2 CO 3 (aq) carbonic acid HClO 4 (aq) perchloric acid H 2 SO 3 (aq) sulfurous acid HNO 2 (aq) nitrous acid H 2 SO 4 (aq) sulfuric acid HNO 3 (aq) nitric acid 22