NOMENCLATURE II. Binary compounds of metals and nonmetals

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1 NOMENCLATURE II Four types of compounds appear in this section. The first type is the binary compounds containing a metal and a nonmetal. The second and third types are ternary compounds; these are either simple ternary compounds or ternary acids. The final category is the hydrates. In some cases, other names may be used; however only those given in this exercise will receive credit in this class. Binary compounds of metals and nonmetals In most cases, a compound containing a metal and a nonmetal or polyatomic ion is ionic. For the ionic compounds covered in this course, the metal will always be present as a cation (positively charged ion). The charges on these ions may be predicted form the position of the element on the Periodic Table. This is simple for the main group (representative) elements. To determine the charge of a main group metal used the number at the top of the column on the Periodic Table. Thus metals in columns IA, IIA, IIIA, IVA, and VA have charges of +1, +2, +3, +4, and +5 respectively. In addition, elements in column IIB are usually +2. There are a few exceptions to this, especially on the right hand side of the Periodic Table. For the metals that you are currently responsible for these exceptions are tin and lead which are often +2, and bismuth which is often +3. (Later you will see how to tell which charge to choose, and how to indicate the value in a name.) You should practice predicting the charges of the metals, which you are responsible for knowing, by looking at a Periodic Table. Remember, these charges do not apply to these metals in their elemental form (where the metal has no charge). That is, the aluminum in a piece of aluminum foil does not have a charge; just the aluminum in a compound such as aluminum chloride is +3. The metal in a binary compound occurs with a nonmetal. The nonmetal will be present as an anion (negatively charged ion). The prediction of the charge on a nonmetal relates to its position on the Periodic Table. However, the counting begins from the opposite side. Thus, nonmetals in columns VIIIA, VIIA, VIA, VA, and IVA have charges of 0, -1, -2, -3, and -4, respectively. The only other nonmetal is hydrogen, which has a charge of -1 when it is combined with a metal. Nonmetals may have other charges, but not in the simple binary compounds with metals covered in this course. In all compounds, the total of all positive and negative charges must be 0. To obtain a net charge of zero it will be necessary to combine the appropriate numbers of cations and anions. Thus a +2 ion could be combined with either a -2 ion or two -1 ions. In some cases the canceling may be a little more involved, for example it takes three +2 ions to cancel two -3 ions. In these cases just keep track of the total charges, so three +2 ions = +6, and two -3 ions = -6, thus the compound has +6-6 = 0. In this case, 6 is the lowest common multiple (LCM) of 2 and 3. The LCM method will work for any binary (or ternary) compound. Some texts use the crisscross rule, instead of the LCM method, for predicting formulas. To use this method use the charge of the anion as the number of cations that are present and use the charge of the cation to predict the number of anions. This rule works directly in most cases, however it is necessary to simplify some the predictions. Examples of these two methods appear below.

2 In all ionic compounds, the name or symbol of the cation must go first. The name or symbol of the anion must go last. The name of the anion has an -ide suffix, the same as they have in binary compounds containing only nonmetals. The major difference when naming binary compounds containing metals is that NO multiplying prefixes are used. Example 1 Give the name and formula of a compound containing aluminum and oxygen. Based on their positions on the Periodic Table aluminum (Al) should have a charge of +3, and oxygen (O) should have a charge of -2. Al 3+ O 2- By the LCM method: The LCM of 3 and 2 is 6, and it takes two 3's and three 2's to equal 6. Thus: Al 2 O 3 By the crisscross rule: Al needs a 2 (from O 2- ) and the O needs a 3 (from Al 3+ ). Thus: Al 2 O 3 Notice, that even though the compound contains +3 and -2 ions, the charges do not appear in the formulas. The name, in this case, will be aluminum oxide. Example 2 Give the formula for a compound containing Pb 4+ and O 2-. Since the charges on the ions are present, it is not necessary to use the Periodic Table. In a situation such as this make sure you do not inadvertently alter the charges, you must use the ones given, whether they make sense or not. By the LCM method: The LCM of 4 and 2 is 4, and it takes one 4 and two 2's. PbO 2

3 By the crisscross method: Pb needs 2 and O needs 4. Pb 2 O 4 This is the problem with using the crisscross method. When you get a formula, such as this one, the subscripts are reducible by a common divisor the subscripts must be reduced. In this case, divide both subscripts by 2, so you should do so: PbO 2 Only after this additional step do you get the same (correct) answer as the LCM method. Ternary compounds of the main group elements The ternary compounds presented in this course normally contain a polyatomic ion. As with the names of the elements, learn the names of these ions directly. In addition to their names and elemental composition, it is also necessary to learn the charges on these ions. Polyatomic ions behave as distinct entities. Thus, both in their names and in chemical formulas containing these ions they remain together. Also when naming these ions, or any ions, as individuals the word ion is part of their name. (The word ion never appears in the name of a compound even if ions are present.) For this course, there are only two polyatomic cations. These cations are the ammonium ion (NH 4 + ) and the mercury(i) ion (Hg 2 2+ ). Treat these two ions as normal metal cations covered in the binary compound section. For example, even though NH 4 Cl is technically a ternary compound, name it like a binary (ammonium chloride). Most of the polyatomic ions covered in this class are anions. Thus, in compounds they are always with a cation. As before, the net charge must be zero. Predict the charges of the cations in the same manner as for binary compounds. The same LCM or crisscross rules are still applicable. Example 3 Give the name and formula for a compound containing aluminum ions and sulfate ions. Al 2 (SO 4 ) 3 aluminum sulfate Notice the sulfate ion requires parentheses to maintain its identity as a single entity of which there are three in this compound. The compound is understood to contain ions, however neither the charges nor the word ion appear anywhere in either the formula or the name.

4 Ternary acids The remaining category of ternary compounds is the ternary acids. These compounds contain hydrogen (as do all acids) and a polyatomic ion. The naming derives from the name of the category of the anion. The categories depend upon the anion suffix. The possible suffixes are -ide, -ite, or -ate. The -ide suffix is not very common for polyatomic ions, and even when it is present the resultant combination of the ion with hydrogen is not necessary an acid. Thus combining hydrogen with a hydroxide ion gives HOH, which is more commonly written as H 2 O, and is water. Hydrogen compounds containing the hydroxide ion, peroxide ion or the superoxide ion are normally not acids. In the cases where the compounds behave as acids, the hydrogen usually appears first in the formula followed by the formula for the polyatomic ion. When naming acids arising from polyatomic ions with an -ide suffix, the binary acids rule is applied (hydro- prefix and -ic acid ending). Example 4: HCN = hydrogen plus cyanide = hydrocyanic acid To name the acid arising when hydrogen is combined with a polyatomic ion with an -ite suffix simply replace the -ite with -ous acid. Thus, the nitrite ion (NO 2 - ) gives nitrous acid (HNO2 ). In a few cases, additional letters are present to make the name easier to pronounce. The only ones that you will be responsible for are those containing sulfur or phosphorus. For example, the sulfite ion (SO 2-3 ) ion gives sulfurous acid (H 2 SO 3 ). Polyatomic anions with an -ate suffix are named by changing the -ate to -ic acid. Using this rule means that the nitrate ion (NO 3 - ) yields nitric acid (HNO 3 ). Again, sulfur and phosphorus use more letters to make them easier to pronounce. Therefore, the phosphate ion (PO 4 3- ) ion changes to phosphoric acid (H 3 PO 4 ). Do not forget, acids are compounds; therefore, the net charge must be zero. The hydrogen is treated as +1 in all acids. Thus, the charge on the anion always tells you how many hydrogen atoms are present. Hydrates The final category of compounds presented in this section is the hydrates. These are examples of a type of compound, which combine two or more different compounds with each of the different compounds retaining its own identity. An example is MgSO 4 7H 2 O. These compounds form because certain other compounds, water in this case, may become very strongly associated with a particular ion or ions. Later in this course, we will see the reasons for this behavior. For nomenclature purposes, the discussion will center only those containing water. The naming is simple just name the non-water portion as a normal compound followed by hydrate. If there is more than one water present, use a multiplying prefix on the hydrate. Thus, this example would be magnesium sulfate heptahydrate. You should consider such compounds as a single unit, just like any simpler compound.

5 Examples Below are some examples of the type of compounds discussed in this section. Look over them and make sure you understand why the names and formulas appear the way that they are. As on the first nomenclature section, these are just a few of the possible compounds, and yes, they all could exist. NaCl sodium chloride AlF 3 aluminum fluoride KNO 3 potassium nitrate CaSO 4 calcium sulfate MgCO 3 magnesium carbonate Zn(MnO 4 ) 2 zinc permanganate CdSO 3 cadmium sulfite Hg 2 (CN) 2 mercury(i) cyanide Li 2 O 2 lithium peroxide Ba(O 2 ) 2 barium superoxide Sr(OCN) 2 strontium cyanate RbSCN rubidium thiocyanate Cs 2 S 2 O 3 cesium thiosulfate Be 3 (PO 4 ) 2 beryllium phosphate K 2 C 2 O 4 potassium oxalate Ra 3 (PO 4 ) 2 radium phosphate Al(NO 2 ) 3 aluminum nitrite RaHPO 4 radium hydrogen phosphate NH 4 NO 3 ammonium nitrate Ra(H 2 PO 4 ) 2 radium dihydrogen phosphate NaOH sodium hydroxide K 2 CrO 4 potassium chromate AlPO 4 aluminum phosphate LiHSO 4 lithium bisulfate or lithium hydrogen sulfate HOH water H 2 O 2 hydrogen peroxide H 2 CO 3 carbonic acid Hg 2 C 2 O 4 mercury(i) oxalate H 2 SO 4 sulfuric acid (NH 4 ) 2 Cr 2 O 7 ammonium dichromate HMnO 4 permanganic acid Al(C 2 H 3 O 2 ) 3 aluminum acetate HCN hydrocyanic acid NaHCO 3 sodium bicarbonate or sodium hydrogen carbonate H 2 S 2 O 3 thiosulfuric acid Na 2 SO 4 10H 2 O sodium sulfate decahydrate HC 2 H 3 O 2 acetic acid CaSO 4 2H 2 O calcium sulfate dihydrate

6 PRACTICE SET II-1 Based on nomenclature section number 1 and 2 1. Aluminum sulfide 1. S 2 F 2 2. Hydroxide ion 2. HNO 2 3. Aluminum iodide 3. K 2 O 4. Sodium acetate 4. Na 2 SO 4 5. Magnesium chromate 5. Cd(CN) 2 6. Phosphorus tribromide 6. TeCl 4 7. Nitric acid 7. MnO 4-8. Calcium dichromate 8. ZnCl 2 9. Aluminum hydroxide 9. KO Calcium thiosulfate 10. Li 3 PO Germanium dibromide 11. P 4 Se Carbonic acid 12. OCN Sodium nitride 13. CaH Magnesium oxalate 14. Zn(MnO 4 ) Barium bisulfate 15. BeHPO Tetraphosphorus hexasulfide 16. S 2 N Cyanic acid 17. PO Lithium carbide 18. BaBr Cesium superoxide 19. SrO Rubidium nitrate 20. Ra(NO 2 ) 2

7 PRACTICE SET II-2 Based on nomenclature section number 1 and 2 1. Digermanium hexachloride 1. SCl 2 2. Ammonium ion 2. H 2 S 2 O 3 3. Sodium thiocyanate 3. CdS 4. Cesium nitrate 4. NaH 2 PO 4 5. Calcium sulfate 5. Zn(CN) 2 6. Diboron trisulfide 6. H 2 O 2 7. Bicarbonate ion 7. PO Calcium acetate 8. Mg 3 P 2 9. Potassium peroxide 9. Cd(MnO 4 ) Barium nitrite 10. Be(H 2 PO 4 ) Nitrogen triiodide 11. AsCl Superoxide ion 12. H 2 CrO Potassium phosphate 13. SrH Aluminum dichromate 14. LiNO Radium phosphate 15. CsOCN 16. Sulfate ion 16. Te 4 I Peroxide ion 17. HSO Rubidium nitride 18. NH 4 Br 19. Potassium cyanide 19. Sr(OH) Sodium thiosulfate 20. CdSO 3

8 PRACTICE SET II-3 Based on nomenclature section number 1 and 2 1. Phosphorus triiodide 1. PBr 5 2. Oxalic acid 2. CsI 3. Cesium carbide 3. Be 3 P 2 4. Ammonium sulfate 4. Rb 2 O 2 5. Magnesium sulfite 5. Ca 3 (PO 4 ) 2 6. Ditellurium bromide 6. AsI 3 7. Acetic acid 7. HCN 8. Radium sulfide 8. Hg 2 I 2 9. Rubidium phosphate 9. NH 4 H 2 PO Ammonium bisulfate 10. BaC 2 O Tetraoxygen difluoride 11. As 4 Se Dichromic acid 12. H 3 PO Aluminum oxide 13. Cd 2 C 14. Mercury(I) chromate 14. Li 2 C 2 O Magnesium bicarbonate 15. Zn(C 2 H 3 O 2 ) Diphosphorus tetraiodide 16. AlF Chromate ion 17. CdCl Mercury(I) chloride 18. Cs 3 N 19. Strontium bicarbonate 19. Rb 2 Cr 2 O Radium oxalate 20. NH 4 C 2 H 3 O 2

9 Based on nomenclature section number 1 and 2 PRACTICE SET II-4 1. Tetraarsenic tetrasulfide 1. AlP 2. Thiocyanate ion 2. Cr 2 O Mercury(I) phosphide 3. KH 4. Cesium phosphate 4. Be(CN) 2 5. Ammonium permanganate 5. Al 2 (SO 3 ) 3 6. Disilicon hexafluoride 6. As 4 S 5 7. Mercury(I) ion 7. C 2 H 3 O 2-8. Calcium oxide 8. LiH 9. Sodium nitrate 9. KNO Magnesium carbonate 10. CdS 2 O Dinitrogen trioxide 11. B 8 Cl Sulfuric acid 12. CO Mercury(I) bromide 13. BaCl Magnesium hydroxide 14. ZnHPO Lithium permanganate 15. Ba(OCN) Aluminum chloride 16. PF Cadmium fluoride 17. Na 2 CO Zinc carbonate 18. SrS 19. Rubidium thiocyanate 19. BeCrO Sodium chromate 20. (NH 4 ) 2 HPO 4

10 Based on nomenclature section number 1 and 2 PRACTICE SET II-5 1. Aluminum oxide 1. As 4 S 3 2. Sulfurous acid 2. H 2 PO 4-3. Rubidium Carbide 3. Be 3 N 2 4. Mercury(I) phosphate 4. AlPO 4 5. Strontium cyanide 5. NH 4 NO 2 6. Germanium tetrafluoride 6. B 9 Cl 9 7. Cadmium oxide 7. HPO Cesium bromide 8. Ra 3 P 2 9. Mercury(I) carbonate 9. Na 2 O Calcium permanganate 10. LiOCN 11. Aluminum chloride 11. S 7 O Thiocyanic acid 12. Zn(SCN) Sodium cyanate 13. ZnI Cesium bisulfate 14. Al(NO 3 ) Magnesium thiosulfate 15. KHSO Selenium trioxide 16. AlI Hydrocyanic acid 17. Mg(C 2 H 3 O 2 ) Ammonium fluoride 18. Li 2 S 19. Mercury(I) hydroxide 19. ZnSO Barium thiocyanate 20. Mg 3 (PO 4 ) 2