CHEMICAL NOMENCLATURE

Transcription

1 CHEMICAL NOMENCLATURE Nomenclature refers to the systematic naming of chemical substances. FORMULA GIVEN NAME Before systematic nomenclature, substances were given common names. These names usually had nothing to do with the elements that made up the compound: Examples: Archaic Name Formula Washing Soda Na 2 CO 3 Lunar Caustic AgNO 3 Oil of Vitriol H 2 SO 4 Systematic Name Fortunately, we do not need to memorize thousands of seemingly random names. Ny knowing a few systems of nomenclature, we can name many substances. VALENCE refers to the actual (or assumed) charge on an atom of an element when it is in a compound. The valence of pure elements is zero. By convention, the element with positive valence is written first, followed by the one with a negative valence. Valence can be predicted through: 1. Position of the periodic table 2. By deduction from the formula. For IONIC compounds, VALENCE is equivalent to the ionic charge. e.g. Predict the valence of each element: SrF 2 CO UO 2 SnS 2 AuI 3 1) SIMPLE BINARY COMPOUNDS contain 2 elements first element has a positive valence; second has a negative valence name of second ends in ide first element has only 1 common valence e.g. MgBr 2 Na 2 O aluminum iodide barium oxide carbide nitride sulfide fluoride chloride iodide hydride silicide phosphide arsenide selenide bromide telluride oxide

2 2)VARIABLE VALENCE BINARY COMPOUNDS These compounds have a first element with 2 (or more) possible positive valences (Refer to Table 1). Three systems have been developed to resolve this problem. I) IUPAC METHOD a Roman numeral is used to indicate the positive valence tin (IV) chloride lead (II) nitride CoS PCl 5 1. I 6. VI 2. II 7. VII 3. III 8. VIII 4. IV 9. IX 5. V 10. X II) ous / ic METHOD names are often based on the Latin names ( cuprum, ferrus, stannum, plumbum, aurum, mercurum) the ous suffix indicates the lower valence the ic suffix indicates the higher valence ferric oxide ferrous oxide PbCl2 CuO III) Greek Prefix Method Greek prefixes can be used to indicate the number of atoms in a compound (unless there is only one of the first element) do not need to consider valences of the elements can be used for any binary compound ( usually nonmetals) P 2 O 5 Mg 3 N 2 nitrogen trifluoride silicon dioxide 1. mono 6. hexa 2. di 7. hepta 3. tri 8. octa 4. tetra 9. nona 5. penta 10. deca

3 TABLE 1: Elements with Two Positive Valences Element Valence(s) IUPAC System ous / ic names Cu copper (I) copper (II) cuprous cupric Hg mercury (I) mercury (II) mercurous mercuric Au Fe Co Ni Pb Sn Mn gold (I) gold (III) iron (II) iron (III) cobalt (II) cobalt (III) nickel (II) nickel (III) lead (II) lead (IV) tin (II) tin (IV) manganese (II) manganese (IV) aurous auric ferrous ferric cobaltous cobaltic plumbous plumbic stannous stannic Group 15 (N, P, As, phosphorus (III) phosphorus (V) phosphorous phosphoric Sb, Bi) S +4 sulfur (IV) sulfurous +6 sulfur (VI) sulfuric NOTE: These transition metals have single valences: Silver (Ag): +1 Zinc (Zn): +2 Therefore no Roman numeral is required.

4 3) BINARY ACIDS acids are compounds that release hydrogen ions (H binary acids contain 2 elements; first is hydrogen dissolved in water (aq = aqueous) + ) Name: hydro ic acid hydrofluoric acid hydrosulfuric acid HCl (g) HCl (aq) 4) BASES contain the polyatomic ion hydroxide (OH ) a polyatomic ion is a group of atoms with a net charge these ions are treated as if they consist of 1 element Lewis structure of hydroxide: sodium hydroxide lead (IV) hydroxide Be(OH) 2 Fe(OH) 2 5) Elements Noble Gases are always monoatomic (1 atom in formula) other gases / halogens are diatomic (2 atoms bonded) metals are always monoatomic in their elemental form helium gas nitrogen gas Fe (s) I 2 (s)

5 SCH3U Naming Simple Binary Compounds PART A: Name the following compounds. e.g. NaF = sodium fluoride 1. NaCl 2. CaCl 2 3. CaO 4. MgBr 2 5. CaS 6. Ag 2 S 7. H 2 O 8. AlI 3 9. Na 2 O 10. Al 4 C Mg 3 N H 2 S 13. AlN 14. SiC 15. Al 2 O KBr PART B: Write the chemical formula for the following compounds. e.g. beryllium nitride = Be 3 N 2 1. aluminum carbide 2. hydrogen oxide 3. aluminum oxide 4. silver sulfide * 5. silicon carbide 6. calcium chloride 7. sodium chloride 8. sodium oxide 9. magnesium bromide 10. calcium sulfide 11. hydrogen sulfide 12. magnesium nitride 13. aluminum iodide 14. calcium oxide 15. aluminum nitride 16 sodium hydride * Silver has a valence of +1.

6 SCH3U1 Determining Valences Valence numbers describe an element s bonding capacity. Positive valences indicate the element tends to give up electrons (e,g. metals) while negative valences indicate elements that tend to gain electrons. Generally, valences tell us the charge of the elements in an ionic bond or the number of shared electrons in a covalent bond. State the valence of each element in the following compounds. If the metal is multivalent (i.e. can have more than one possible charge), deduce the charge based on the valence of the non-metal. e.g. Fe 2 O 3 Fe is +3 and O is -2. HBr NaF HF SnCl 2 H 2 O Sb 2 O 3 NH 3 Na 2 S N 2 O 3 PbS CH 4 PbO 2 SiCl 4 MgS CO 2 ZnI 2 PCl 3 CaBr 2 PCl 5 BaO AsCl 3 Al 2 O 3 AsCl 5 MnCl 2 HI SO 2 AgI SO 3 Cu 2 O BCl 3 CuO SbCl 5 Hg 2 O SbCl 3 HgI 2 LiF SnF 4 BeI 2 KI NiBr 2 FeO H 2 S

7 SCH3U1 Nomenclature of Variable Valence Binary Compounds Write the chemical formula or the chemical name for each of the following using the system indicated. PART A: The IUPAC Method 1. PbO 2. As 2 S 5 3. Fe 2 O 3 4. CuI 2 5. SnO 6. SbCl 2 7. P 2 O 3 8. MnO 2 9. mercury (I) chloride 10. iron (III) oxide 11. antimony (III) iodide 12. phosphorus (V) oxide 13 tin (II) oxide 14. copper (II) bromide PART B: The ous / -ic Method 1. SnCl 4 2. Sb 2 O 3 3. CuBr 2 4. FeBr 2 5. Fe 2 S 3 6. HgI 7. mercurous chloride 8. antimonous chloride 9. phosphoric sulfide 10. ferric oxide 11. phosphorous oxide 12. mercuric chloride 13. stannous bromide 14. cuprous iodide 15. phosphoric oxide 16. arsenic sulfide 17. stannic fluoride 17. ferrous oxide PART C: The Greek Prefix Method 1. SO 3 2. As 2 S 5 3. PbO 4. N 2 O 3 5. carbon dioxide 6. manganese dioxide 7. phosphorus trichloride 8. carbon monoxide 9. diarsenic trioxide 10. lead dioxide 11. copper monochloride 12. sulfur trioxide 13. carbon tetrachloride 14. diphosphorus pentoxide

8 Binary Compounds (all types) Write the chemical formula for each compound. 1. sulfur (VI) fluoride 11. manganese (VII) oxide 2. mercuric iodide 12. manganese monoxide 3. tin (IV) chloride 13. stannous nitride 4. potassium nitride 14. dinitrogen monoxide 5. beryllium iodide 15. boron sulfide 6. rubidium phosphide 16. antimony (III) fluoride 7. iron (III) oxide 17. plumbous sulphide 8. sulphur (VI) oxide 18. sulphur hexafluoride 9. sulphurous oxide 19. copper (II) oxide 10. diarsenic trioxide 20. xenon difluoride Write the name of the following compounds using the system indicated. 1. F 2 O (Greek Prefix)) 2. AuCl 3 (IUPAC) 3. N 2 Cl 4 (Greek Prefix) 4. HCl (simple binary) 6. Al 4 C 3 (simple binary) 7. CaC 2 (Greek Prefix) 8. Cu 2 S (-ous/-ic) Write three possible names for the following compounds. 1. Fe 2 O 3 2. SF 6

9 SCH3U1 Binary Compounds, Binary Acids, Bases and Gases A. Name these compounds using the IUPAC method: 1. CuCl 4. Fe 2 O 3 2. SnBr 2 5. As 2 S 5 3. SO 2 6. MnO 2 B. Name these compounds using the ous/-ic method: 1. HgCl 2 4. FeCl 3 2. Sb 2 O 3 5. CuBr 3. FeO 6. As 3 N 5 C. Name these compounds using the Greek Prefix method: 1. PbO 2 4. HgO 2. As 2 S 3 5. SI 5 3. SO 3 6. CCl 4 D. Write the correct formula for each compound: 1. mercuric bromide 9. ferrous oxide 2. tin (II) iodide 10. calcium hydroxide 3. diantimony pentoxide 11. hydroiodic acid 4. magnesium nitride 12. silver sulfide 5. oxygen gas 13. hydrosulfuric acid 6. zinc hydroxide 14. barium sulfide 7. tin (II) oxide 15. carbon monoxide 8. aluminum hydroxide 16. hydrophosphoric acid E. Write an acceptable systematic name beside these archaic names. 1. lime (CaO) 2. antimony black (Sb 2 S 3 ) 3. slaked lime (Ca(OH) 2 )

10 Binary Compounds, Binary, Bases and Gases (continued) Note: aq = aqueous state (dissolved in water); g = gas state; l = liquid state 1. Give the chemical formula for each compound. sodium oxide aluminum carbide potassium iodide mercuric oxide silicon oxide iron (III) hydroxide phosphorous iodide magnesium nitride calcium bromide beryllium hydroxide sodium hydride hydrogen oxide hydroiodic acid hydrofluoric acid (aq) ferrous sulphide hydrogen fluoride gas (g) hydrosulfuric acid mercury (I) chloride iron (II) hydroxide magnesium hydroxide arsenous fluoride nitrogen gas (g) antimony (V) sulfide helium gas (g) 2, Name these compounds. SO 3 As 2 S 3 AgO HI (g) Ba(OH) 2 HBr (aq) SnO Ag 2 S SbCl 5 CuOH Xe (g) Br 2 (l) CoCl 2 H 2 (g) HBr (g) SO 2 PbOH) 4 SeCl 6 AgOH

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