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Naming Covalent/ Molecular Compounds. Naming Covalent Compounds. Hydrogen compounds are handled differently and will be looked at first. Nomenclature: 1) Name the hydrogen that appears in the formula.
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Naming Covalent Compounds Hydrogen compounds are handled differently and will be looked at first. Nomenclature: 1) Name the hydrogen that appears in the formula. 2) Name the second element that appears in the formula, changing its ending to –ide. Examples: HCl hydrogen chloride HI hydrogen iodide
Covalent Bonds use Prefixes to indicate the number of atoms involved in the compounds 1= mono 6 = hexa 2 = di 7= hepta 3 = tri 8 = octa 4 = tetra 9 = nona 5 = penta 10 = deca
RULES 1- The name of the first element does not get changed, only a prefix is added if it is more than one. Ex: Trisulfur tetrafluoride S3F4 2- The second element gets a different ending, as well as a prefix. Ex : phosphorus trichloride PCl3 (NOT: phosphorustrichlorine)
RULES continued.. 3- If the first element in the compound is single you do not write mono: ex. CO2 - carbon dioxide (NOT monocarbon dioxide) 4- If the element’s name starts with a vowel, and the prefix ends with a vowel, you can drop the last vowel on the prefix: ex. S5O10 - pentasulfur decoxide (NOT pentasulfur decaoxide)
RULES continued.. 5- Covalent compounds do not get simplified. Name the compound exactly as you see it: Ex. H2F2 = dihydrogen difluoride (NOT hydrogen monofluoride HF)
Naming Covalent Compounds What is the name of SO3? STEP 1 The first nonmetal is S sulfur. STEP 2 The second nonmetal is O, named oxide. STEP 3 The subscript 3 of O is shown as the prefix tri. SO3→ sulfur trioxide The subscript 1(for S) or mono is understood.
Naming Covalent Compounds (Continued) Name P4S3 STEP 1 The first nonmetal P is phosphorus. STEP 2 The second nonmetal S is sulfide. STEP 3 The subscript 4 of P is shown astetra. The subscript 3 of O is shown as tri. P4S3→tetraphosphorus trisulfide
Names of Covalent Compounds Remember Prefixes are used • in the names of covalent compounds • because two nonmetals can form two or more different compounds Examples of compounds of N and O: NO nitrogen oxide NO2 nitrogen dioxide N2O dinitrogen oxide N2O4 dinitrogentetroxide N2O5 dinitrogenpentoxide
Learning Check Select the correct name for each compound. A. SiCl4 1) silicon chloride 2) tetrasilicon chloride 3) silicon tetrachloride B. P2O5 1) phosphorus oxide 2) phosphorus pentoxide 3) diphosphorus pentoxide C. Cl2O7 1) dichlorine heptoxide 2) dichlorine oxide 3) chlorine heptoxide
Solution Select the correct name for each compound. A. SiCl4 3) silicon tetrachloride B. P2O5 3) diphosphorus pentoxide C. Cl2O7 1) dichlorine heptoxide
Learning Check Write the correct formula for each of the following: A. phosphorus pentachloride B. dinitrogen trioxide C. sulfur hexafluoride
Solution Write the correct formula for each of the following: A. phosphorus pentachloride 1P penta = 5Cl PCl5 B. dinitrogen trioxide di = 2N tri = 3 O N2O3 C. sulfur hexafluoride 1S hexa = 6F SF6
TRY THESE: • Diphosphorus pentoxide • Nitrogen monoxide • Xenon hexafluoride • Tetrarsenic decoxide
More Examples a) SiO2 b) N2S5 c)P4O10 d)BrCl6
Name the following binary molecular compounds: (a) NF3 and (b) N2O4. Strategy Each compound will be named using the systematic nomenclature. Solution (a) nitrogen trifluoride (b) dinitrogen tetroxide Think About It Make sure that the prefixes match the subscripts in the molecular formulas and that the word oxide is not preceded immediately by an “a” or an “o”.
Write the chemical formulas for the following binary molecular compounds: (a) sulfur tetrafluoride and (b) tetraphosphorus decasulfide. Strategy The formula for each compound will be deduced using the systematic nomenclature guidelines. Solution (a) SF4 (b) P4S10 Think About It Double-check that the subscripts in the formulas match the prefixes in the compound names: (a) 4 = tetra and (b) 4 = tetra and 10 = deca.
Learning Check Write the name of each covalent compound. CO _____________________ CO2 _____________________ PCl3 _____________________ CCl4 _____________________ N2O _____________________
Solution Write the name of each covalent compound. CO carbon monoxide CO2 carbon dioxide PCl3 phosphorus trichloride CCl4 carbon tetrachloride N2O dinitrogen oxide
Review of Covalent Compounds HI hydrogen iodide NF3 nitrogen trifluoride SO2 sulfur dioxide N2Cl4 dinitrogen tetrachloride NO2 nitrogen dioxide N2O dinitrogen monoxide
Ionic and Covalent Identify each compound as ionic or covalent, and give its correct name. A. SO2 B. BaCl2 C. (NH4)3PO4 D. Cu2CO3 E. N2O4
Solution Identify each compound as ionic or covalent, and give its correct name. A. SO2 covalent; sulfur dioxide B. BaCl2 ionic; barium chloride C. (NH4)3PO3 ionic; ammonium phosphite D. Cu2CO3 ionic; copper(I) carbonate E. N2O4 covalent; dinitrogen tetroxide
Learning Check Name the following compounds: A. Ca3(PO4)2 B. FeBr3 C. SCl2 D. Cl2O
Solution Name the following compounds: A. Ca3(PO4)2 ionic Ca2+, PO43−calcium phosphate B. FeBr3 ionicFe3+, Br−iron(III) bromide C. SCl2 covalent 1S, 2Cl sulfur dichloride D. Cl2O covalent 2Cl, 1 O dichlorine oxide