Chemical Formulae Ionic versus MolecularCovalent Ionic compounds typically

Chemical Formulae • Ionic versus Molecular/Covalent – Ionic compounds typically feature a metal (cation) and a nonmetal (anion). – Molecular compounds are composed of nonmetals exclusively. – Both must be electrically neutral in charge. – Nomenclature (naming) has similarities… the differences occur because of the law of multiple proportions. • The same elements can make multiple, different compounds. . . Roman numerals or prefixes are used. 1

Molecular Formulae • Formula Structure – Elements present – Subscripts* (shows how much of each element) CO 2 This is carbon dioxide If no subscript is present it means that there is only one atom of that element * This is a molecule of a molecular compound 2

Molecular Nomenclature Naming Rules – Write the names of both elements. • You will only learn covalent naming for binary compounds – Change the ending of the second element to ide. – Add prefixes to each element to indicate the subscripted number of atoms present. • If the first element only has one atom then no prefix carbon dioxide oxygen is added. Example: CO 2 becomes 3

Molecular Nomenclature • Prefixes - Greek prefixes used… 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. monodi– tritetrapentahexaheptaoctanonadeca- - The final “o” or “a” of the prefix is usually dropped when preceding an element beginning with a vowel. 4

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ S 4+ S 2+ S As 2 Se As As. Br As. F As As. Cl S 53343533 As As. I S 242 Se 3 O 17+ 5+ Cl 3+ diarsenic Cl Cl Cl diarsenic tetraarsenic monoseleni As 3+ pentachloride As 3 pentasulfide tribromide trifluoride triselenide pentoxide trichloride trisulfide tetrasulfide triiodide trioxide de As 5+ Se 4+ Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 5 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ S 4+ S 2+ S B BBr BCl BF Cl C 334 B BN 224 O 33 17+ 5+ Cl 3+ Cl Cl diboron Cl tetraboron diboron nitride trioxide 3+ monocarbide tetrachloride tribromide trichloride trifluoride As As 3 As 5+ Se 4+ Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 6 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ S 4+ S 2+ S CCl CSe CN CO CF CO CS CI 4422 442 17+ Cl Cl Cl 5+ Cl 3+ carbon tetrachloride tetranitride diselenide dioxide tetrafluoride tetraiodide monoxide disulfide As 3+ As 3 As 5+ Se 4+ Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 7 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3+ Cl O P 3 - S 6+ 2 2 - Cl 1+ Cl. O Cl. F 2 S 4+ S 2+ S Cl. F Cl 2 O dichlorin 37 chlorine chlorin 17+ Cl Cl Cl 5+ Cl 3+ dichlorine e monofluorid e 3+ 3 trifluoride heptoxide monoxid As As dioxide e 4+ 5+ e As Se Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 8 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ Ge. Cl IF ICl 5 4 7 S 4+ S 2+ S Ge. F IF O O 35242 Ge. Cl F H ICl O 222 germanium iodine 17+ Cl Cl Cl 5+ Cl 3+ germanium diiodine dihydrogen fluoride iodine pentafluorid heptafluorid monochlorid tetrachlorid 3+ 3 tetrafluoride pentoxide monoxide trichloride dioxide As As eee 4+ 5+ As Se Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 9 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ S 4+ S 2+ S NN NCl NO NH NO S N NF O 323454 424 Se 2 O 17+ Cl Cl Cl 5+ Cl 3+ tetranitrogen dinitrogen tetraselenide tetrasulfide pentoxide trihydride chloride dioxide monoxide fluoride As 3+ As 3 As 5+ Se 4+ Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 10 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ PP 44 Se S 33 S 4+ S 2+ S P 22 Se O S 5353535 PCl PH PF P tetraphosphoru 17+ Cl Cl diphosphorus Cl 5+ Cl 3+ phosphorus s 3+ 3 trichloride pentasulfide pentoxide pentachloride pentafluoride trihydride pentaselenide trioxide As As trisulfide 4+ triselenide 5+ As Se Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 11 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ S 4+ S 2+ S S Se Se. Cl Se. F Cl Se. S 22 Cl Se. O SO SF SO 22 424 6 342 17+ 5+ Cl 3+ Cl Cl Cl disulfur diselenium sulfur dichloride tetrafluoride As 3+ As 3 disulfide hexafluoride dioxide trioxide As 5+ Se 4+ Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 12 Go To Next Slide

Molecular Compound Formulae (Molecules) B 3+ C 4 C 2+ C 2 - N 3+ N 3 - N 5+ N 4+ N 2+ O 2 - O 1 - F 1 - Si 4+ Si 2+ P 5+ P 3 - S 6+ 2 - Cl 1+ S 4+ S 2+ S Si Si. Cl Si. O Si. S Si. F Si. O Si. C Te. Cl Te. I 3 N 42444 2 17+ Cl Cl Cl 5+ Cl 3+ trisilicon tellurium tetrafluoride tetranitride monoxide disulfide dioxide tetrachloride tetraiodide dichloride As 3+ monocarbide As 3 As 5+ Se 4+ Se 6+ Se 2 - Br 1+ Br 1 Br 7+ Br 5+ Br 3+ Te 4+ Te 6+ Te 2 - I 7+ I 5+ I 1 - At 1+ At 1 - At 7+ At 5+ At 3+ 13 Go To Next Slide