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By John Weide with modifications by Ken Costello.

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1 By John Weide with modifications by Ken Costello

2 Compounds are two or more elements that are held together by opposite charge attraction. Oxygen-8 Magnesium-12 8 (+) 10 (-) -2 Charge 12 (+) 10 (-) +2 Charge Metal Non-metal

3 Metals combine with non-metals Metals loose electrons to non-metals They then attract because their charges will be opposite.

4 -3 -2 Most of the negative ions have a set negative charge

5 +1 +2 +3 +1 +2 -3 -2

6 For example the oxy-salts of chlorine, bromine and iodine have many trends in common. Look for them below…… perchlorate ClO 4 -1 chlorate ClO 3 -1 chlorite ClO 2 -1 hypochlorite ClO -1 perbromate BrO 4 -1 bromate BrO 3 -1 bromite BrO 2 -1 hypobromite BrO -1 periodate IO 4 -1 iodate IO 3 -1 iodite IO 2 -1 hypoiodite IO -1 The next table contains the polyatomic ions that need to be committed to memory. Remember to learn the name, formula and oxidation number

7 POLYATOMIC IONS (charged building blocks) Polyatomic ions are mostly made of two non-metals. Ions with -1 charge perbromate BrO 4 -1 bromate BrO 3 -1 bromite BrO 2 -1 hypobromite BrO -1 perchlorate ClO 4 -1 chlorate ClO 3 -1 chlorite ClO 2 -1 hypochlorite ClO -1 periodate IO 4 -1 iodate IO 3 -1 iodite IO 2 -1 hypoiodite IO -1 nitrateNO 3 -1 nitriteNO 2 -1 hydroxideOH -1 cyanideCN -1 acetateC 2 H 3 O 2 -1 PermanganateMnO 4 -1 bicarbonateHCO 3 -1 Ions with a -2 Charge carbonateCO 3 -2 sulfateSO 4 -2 sulfite SO 3 -2 chromate CrO 4 -2 dichromate Cr 2 O 7 -2 oxalate C 2 O 4 -2 Ions with a -3 Charge phosphate PO 4 -3 phosphite PO 3 -3 arsenate AsO 4 -3 Ions with +1 charge ammonium ion NH 4 +1

8 Ions with -1 charge perbromate BrO 4 -1 bromate BrO 3 -1 bromite BrO 2 -1 hypobromite BrO -1 perchlorate ClO 4 -1 chlorate ClO 3 -1 chlorite ClO 2 -1 hypochlorite ClO -1 periodate IO 4 -1 iodate IO 3 -1 iodite IO 2 -1 hypoiodite IO -1 These polyatomic ions match the charge of the single element

9 -2 These polyatomic ions match the charge of the single element Ions with a -2 Charge sulfateSO 4 -2 sulfite SO 3 -2 Ions with a -3 Charge phosphate PO 4 -3 phosphite PO 3 -3 -3

10 It is also important to memorize the oxidation of the ions that have fixed oxidation numbers (positive or negative). In particular, those from groups 1A, 2A, 3A, 4A, 5A, 6A, 7A, 8A and the elements: Zn, Cd and Ag. Use the following periodic chart to determine their oxidation numbers. Just click on the element symbol…

11 N Elements with Fixed Oxidation Numbers LaHfTaReOsCeBaTl Pb BiPoAtRnIrPtAuHg YZrNbMoTcRuRbSrInSnSbTeIXeRhPdAgCd ScTiVCrMnFeKCaGaGeAsSeBrKrCoNiCuZn AlSiPSClArNaMg BCOFNeLiBe HHHe AcRfDbSgRhHsFrRaMt +1+2+3 1A 2A 8A 0-4-3-2 7A 6A5A4A3A W NdPmSmEuGdTbCePrYbLuDyHoErTm NpAmCmBkThPaNoLrCfEsFmMdUPu Click on element to see its oxidation number(s) Next Slide

12 Naming Ionic Compounds The positive ion (usually a metal) is named first while the negative ion (a non-metal or a polyatomic ion) is named last. The charge on the negative ion is used to determine the charge on the positive ion. In-order for the total oxidation state to be zero, the total positive charge must equal the total negative charge. A simple algebraic equation can be used to determine the charge on a single metal ion. This charge is expressed as a Roman Numeral in parenthesis that immediately follows the name of the metal. CuSO 4 Cu ? SO 4 -2 x +(-2)=0 X = 2 Copper (II) Sulfate

13 Naming Ionic Compounds The positive ion (usually a metal) is named first while the negative ion (a non-metal or a polyatomic ion) is named last. The charge on the negative ion is used to determine the charge on the positive ion. In-order for the total oxidation state to be zero, the total positive charge must equal the total negative charge. A simple algebraic equation can be used to determine the charge on a single metal ion. This charge is expressed as a Roman Numeral in parenthesis that immediately follows the name of the metal. Cu 2 SO 4 Cu 2 +x SO 4 -2 2x +(-2)=0 x = 1 Copper (I) Sulfate

14 Naming Ionic Compounds If the positive ion is one that has a fixed oxidation number then no Roman Numeral is used. Everyone should know the charge of fixed ions. These include metals in group 1A, 2A and the specific metals: Al, Zn, Cd & Ag (zinc, cadmium and silver). CaSO 4 Calcium Sulfate No Roman Numeral

15 If the ionic compound is binary it will end in -ide. However, not all compounds that end in -ide are binary. For example sodium hydroxide has the formula…NaOH (three different kinds of atoms). If the negative ion is a polyatomic ion the compound is no longer binary. The ending will be that carried by the polyatomic ion. These endings are either -ate or - ite. Hydrated compounds are named using a combination of both the stock system and prefixes. A prefix is used to denote the number of water molecules attached to the ionic formula. hydrate is used as the name indicating that water is attached. For example, copper(II) sulfate pentahydrate has the formula CuSO 4. 5H 2 O

16 Examples #1- Formulas to Names CuSO 3 copper Im a polyatomic ion 1.Write the names of the ions Final Name sulfite (II) x X + (- 2) = 0 X = +2 Cu SO 3 = 0 You must know the charge on the sulfite ion is -2 The sum of the positive and negative charges must equal zero 2. Determine the charge of the positive ion -2 +2 Next +2

17 Examples #2- Formulas to Names KMnO 4 potassium Im a polyatomic ion 1.Write the names of the ions Final Name permanganate If the positive ion has a fixed charge, you are finished.

18 Examples #3- Formulas to Names NH 4 NO 3 ammonium Im a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name nitrate If the positive ion has a fixed charge, you are finished.

19 Examples #4- Formulas to Names SnF 2 tin 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name fluoride (II) Sn x (F -1 ) 2 = 0 X + 2(-1) = 0 X = +2

20 Examples #5- Formulas to Names Ba(ClO 4 ) 2 barium Im a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name perchlorate If the positive ion has a fixed charge, you are finished.

21 Examples #6- Formulas to Names Cu 2 S copper Im not a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name sulfide (I) 2Cu x (S) -2 = 0 2X + (-2) = 0 X = +1

22 Examples #6- Formulas to Names Cu 2 S copper 1.Write the names of the ions Final Name sulfide (I) x 2X + (- 2) = 0 2X = +2 (Cu ) 2 S You must know the charge on the sulfide ion is -2 The sum of the positive and negative charges must equal zero 2. Determine the charge of the positive ion -2 +2 Next +1 2 X = +1

23 Examples #7- Formulas to Names Na 2 Cr 2 O 7 sodium Im a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name dichromate (I) 2(Na x )(Cr 2 O 7 ) -2 = 0 2X + (-2) = 0 X = +1 If the positive ion has a fixed charge, it is not shown

24 Examples #10- Formulas to Names LiCN lithium Im a polyatomic ion 2.Determine the charge of the positive ion 1.Write the names of the ions Final Name cyanide If the positive ion has a fixed charge, you are finished.

25 Writing Ionic Formulas It is easier to write the formula of an ionic compound from its name than the reverse. The oxidation number of the negative ion must be memorized in all cases. Refer to the table of polyatomic ions.

26 aluminum chloride What is the Lowest Common Multiple LCM of 3 and 1. Do not worry about the sign(+/-) Example #1-Names to Formulas Al Cl 3 2. Determine number of ions 1. Write symbols of elements Final Formula (Al ) x (Cl -1 ) y = 0 1 If there is only one atom the 1 is not shown +3 If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion. Next

27 Example #1-Names to Formulas aluminum chloride Al Cl 3 2. Determine number of ions 1. Write symbols of elements Final Formula x(+3) + y(-1) = 0 1 For aluminum, a 1 is multiplied times the +3 to give a +3 charge If there is only one atom the 1 is not shown If there is no Roman Numeral, you must know the oxidation number of the positive ion. +3 If there is no Roman Numeral, you must know the oxidation number of the positive ion. What is the Lowest Common Multiple LCM of 3 and 1. Do not worry about the sign(+/-) (Al ) x (Cl -1 ) y What is the Lowest Common Multiple LCM of 3 and 1. Do not worry about the sign(+/-) For chloride, a 3 is multiplied times the -1 to give a -3 charge 1(+3) + 3(-1) = 0 Remember all compounds are neutral, thus the total positive charge must equal the total negative charge Next This formula says that the +3 charge of one Al atom will cancel the-3 charge from 3 Cl atoms

28 Example #2-Names to Formulas cobalt(II) bromate Co BrO 3 2. Determine number of ions 1. Write symbols of elements Final Formula (Co +2 ) x (BrO 3 -1 ) y = 0 2X = 1y X(+2) + y(-1) = 0 X 1 Y 2 = 1 Choose the lowest set of integers that satisfies the equation (BrO 3 ) 2 If there is only one atom the 1 is not shown Next

29 Example #3-Names to Formulas nickel(III) acetate Ni C2H3O2C2H3O2 2. Determine number of ions 1. Write symbols of elements Final Formula (Ni +3 ) x (C 2 H 3 O 2 -1 ) y = 0 3X = 1y X(+3) + y(-1) = 0 X 1 Y 3 = 1 Choose the lowest set of integers that satisfies the equation (C 2 H 3 O 2 ) 3 If there is only one atom the 1 is not shown Next

30 Example #4-Names to Formulas lithium phosphate Li PO 4 2. Determine number of ions 1. Write symbols of elements Final Formula (Li ) x (PO 4 -3 ) y = 0 1X = 3y X(+1) + y(-3) = 0 X 3 Y 1 = 3 +1 Choose the lowest set of integers that satisfies the equation (PO 4 ) 1 If there is only one atom the 1 is not shown If there is no Roman Numeral, you need to know the fixed oxidation number of the positive ion. Next

31 Practice Problems By now you should have an idea of what is expected when naming covalent binary compounds using prefixes. In order to master this naming system you need to practice until you feel proficient in naming compounds using prefixes.

32 Practice Problem #1 Fe(NO 3 ) 3 Choose the correct name for the compound 1. Iron trinitrate 2. iron(I) nitrate 3. iron(III) nitrite 4. iron(III) nitrate 5. none of the above next problem Polyatomic IonsPeriodic Chart

33 Practice Problem #2 sodium chlorite Choose the correct formula for the compound 1. NaCl 2. NaClO 3. NaClO 2 4. Na(ClO) 2 5. none of the above next problem Prefixes Periodic Chart

34 POLYATOMIC IONS Ions with -1 charge perbromate BrO 4 -1 bromate BrO 3 -1 bromite BrO 2 -1 hypobromite BrO -1 perchlorate ClO 4 -1 chlorate ClO 3 -1 chlorite ClO 2 -1 hypochlorite ClO -1 periodate IO 4 -1 iodate IO 3 -1 iodite IO 2 -1 hypoiodite IO -1 nitrate NO 3 -1 nitrite NO 2 -1 hydroxide OH -1 cyanide CN -1 thiocyanate SCN -1 acetate C 2 H 3 O 2 -1 Permanganate MnO 4 -1 bicarbonate HCO 3 -1 Ions with a -2 Charge carbonate CO 3 -2 phthalate C 8 H 4 O 4 -2 sulfate SO 4 -2 sulfite SO 3 -2 chromate CrO 4 -2 dichromate Cr 2 O 7 -2 oxalate C 2 O 4 -2 peroxide O 2 -2 Ions with a -3 Charge phosphate PO 4 -3 phosphite PO 3 -3 arsenate AsO 4 -3 Ions with +1 charge ammonium ion NH 4 +1 return

35 N Oxidation Numbers (most common) LaHfTaReOsCeBaTl Pb BiPoAtRnIrPtAuHg YZrNbMoTcRuRbSrInSnSbTeIXeRhPdAgCd ScTiVCrMnFeKCaGaGeAsSeBrKrCoNiCuZn AlSiPSClArNaMg BCOFNeLiBe HHHe AcRfDbSgRhHsFrRaMt +1+2+3 1A 2A 8A 0-4-3-2 7A 6A5A4A3A W NdPmSmEuGdTbCePrYbLuDyHoErTm NpAmCmBkThPaNoLrCfEsFmMdUPu Click on element to see its oxidation number(s) +1+2 +3+2+4 return


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