Chem. 125-126: Oct. 1 - Oct. 7 Preparation Pre-lab Report (p.90) for E3 completed Discussion Presentation for E2 completed Pre-lab reading and studies for E3 completed Agenda One hour discussion of E2(Questions, p.73) Two hours of E3; E3= two session 5 hour lab E3: Redox: Transferring Electrons Session 1: Two our Lab Agenda* Complete Part 1 Complete Part 2A Complete Team Report (Parts 1 and 2A) * See Student Information Sheet on Ctools under Resources Experiments. Session 2: Three our Lab Agenda Complete Parts 2B and 3 Background Information: Redox Oxidation-reduction reaction = redox reaction Redox reactions involve electron transfer.
Loss of electrons (LEO) = oxidation Gain of electrons (GER) = reduction 1A VIIIA 1 2 e 1s 1 IIA IIIA IVA VA VIA VIIA 1s 2 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne 2s 1 2s 2 2s 2 2p 1 2s 2 2p 2 2s 2 2p 3 2s 2 2p 4 2s 2 2p 5 2s 2 2p 6 11 Na 3s 1 19 K 4s 1 37 Rb 5s 1 55 Cs 6s 1 87 Fr 7s 1 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar 3s 2 IIIB IVB VB VIB VIIBVIIIB VIIIB IB IIB 3s 2 3p 1 3s 2 3p 2 3s 2 3p 3 3s 2 3p 4 3s 2 3p 5 3s 2 3p 6 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 4s 2 3d 1 4s 2 3d 2 4s 2 3d 3 4s 2 3d 5 4s 1 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 2 4s 2 4p 1 4s 2 4p 2 4s 2 4p 3 4s 2 4p 4 4s 2 4p 5 4s 2 4p 6 3d 10 4s 1 3d 10 4s 2 38 Sr 5s 2 56 Ba 6s 2 88 Ra 7s 2 39 40 41 42 43 44 45 46 Y Zr Nb Mo Tc Ru Rh Pd 4d 1 5s 2 4d 2 5s 2 4d 3 5s 2 4d 5 5s 1 4d 5 5s 2 4d 7 5s 1 4d 8 5s 1 4d 10 57 La* 5d 1 6s 2 Background Information: Redox Metals lose electrons (LEO) Non-metals gain electrons GER) 47 Ag 4d 10 5s 1 48 Cd 4d 10 5s 2 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe 5s 5p 1 5s 5p 2 5s 5p 3 5s 5p 4 5s 2 5p 5 5s 5p 6 72 f 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 g 81 Tl 82 83 Bi 84 Po 85 At 86 Rn 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 5d 5 6s 2 5d 6 6s 2 5d 7 6s 2 5d 9 6s 1 6s 2 6p 1 6s 2 6p 2 6s 2 6p 3 6s 2 6p 4 6s 2 6p 5 6s 2 6p 6 5d 10 6s 1 5d 10 6s 2 89 104 105 106 107 108 109 + Element synthesized, Ac # + + + + + + but no official name assigned 6d 1 7s 2 6d 2 7s 2 6d 3 7s 2 6d 4 7s 2 6d 5 7s 2 6d 6 7s 2 6d 7 7s 2 +1 1 Oxidation State Family A Metals (p.223) 1A +3 +4 +5 +6 1 +2 2 1s 1 IIA 3 4 Li Be 2s 1 2s 2 Q. Oxidation states of Sn? +1 +2 +3 +4 13 14 15 16 17 VIIA IIIA IVA VA VIA 11 12 13 Na Mg 3s 1 3s 2 3 4 5 6 7 8 9 10 11 12 Al VIIIB IIIB IVB VB VIB VIIB VIIIB IB IIB 3s 2 3p 1 19 20 21 22 23 24 25 26 27 28 29 30 31 32 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge 4s 1 4s 2 4s 2 3d 1 4s 2 3d 2 4s 2 3d 3 4s 1 3d 5 4s 2 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 1 3d 10 4s 2 3d 10 4s 2 4p 1 4s 2 4p 2 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb 5s 1 5s 2 5s 2 4d 12 5s 2 4d 2 5s 2 4d 3 5s 1 4d 5 5s 2 3d 5 5s 1 4d 7 5s 1 4d 8 4d 10 5s 1 4d 10 5s 2 4d 10 5s 2 5p 1 5s 2 5p 2 5s 2 5p 3 55 56 57 72 73 74 75 76 77 78 79 80 81 82 83 84 Cs Ba La* f Ta W Re Os Ir Pt Au g Tl Bi Po 6s 1 6s 2 6s 2 5d 1 6s 2 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 4d 5 6s 2 5d 6 5d 7 6s 2 6s 1 5d 9 6s 1 5d 10 6s 2 5d 10 6s 2 6p 1 6s 2 6p 2 6s 2 6p 3 6s 2 6p 4 87 88 89 104 105 106 107 108 109 + Element synthesized, Fr Ra Ac # + + + + + + 7s 1 7s 2 7s 2 6d 1 7s 2 6d 2 7s 2 7d 3 7s 2 6d 4 7s 2 3d 5 6s 2 6d 6 6d 7 7s 2 but no official name assigned Sn = 18 VIIIA
1 Transition Metals 1A Q. Maximum oxidation state vs. family #? 1 2 13 14 15 16 1s 1 IIA IIIA IVA VA VIA 3 4 Li Be 2s 1 2s 2 +2 +2 +2 +2 +2 11 12 +3 +4 +5 +6 +7 +2 +1 +2 13 Na Mg 3 4 5 6 7 8 9 10 11 12 Al 3s 1 3s 2 IIIB IVB VB VIB VIIB VIIIB VIIIB IB IIB 3s 2 3p 1 19 K 4s 1 20 Ca 4s 2 21 Sc 4s 2 3d 1 22 23 24 25 26 27 28 29 Ti V Cr Mn Fe Co Ni Cu 4s 2 3d 2 4s 2 3d 3 4s 1 3d 5 4s 2 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 1 3d 10 37 38 39 Rb Sr Y 40 Zr 41 Nb 42 Mo 43 Tc 44 Ru 45 Rh 46 Pd 5s 1 5s 2 5s 2 4d 1 5s 2 4d 2 5s 2 4d 3 5s 1 4d 5 5s 2 3d 5 5s 1 4d 7 5s 1 4d 8 4d 10 55 Cs 6s 1 87 Fr 7s 1 56 Ba 6s 2 47 Ag 5s 1 4d 10 30 Zn 4s 2 3d 10 31 Ga 4s 2 4p 1 32 Ge 4s 2 4p 2 48 Cd 5s 2 4d 10 49 In 50 Sn 51 Sb 5s 5p 1 5s 5p 2 5s 5p 3 57 72 73 74 75 76 77 78 79 80 81 82 83 84 La* f Ta W Re Os Ir Pt Au g Tl Bi Po 6s 2 5d 1 6s 5d 6s 5d 3 6s 5d 6s 4d 6s 5d 6 5d 6s 2 6s 5d 6s 2 6p 1 6s 2 6p 2 6s 2 6p 3 6s 2 6p 4 2 2 2 2 4 7 1 9 6s 1 5d 10 6s 2 5d 10 88 89 104 105 106 107 108 109 + Element synthesized, Ra Ac # + + + + + + but no official name assigned 7s 2 7s 2 6d 1 7s 2 6d 2 7s 2 7d 3 7s 2 6d 4 7s 2 3d 5 6s 2 6d 6 6d 7 7s 2 17 VIIA 18 VIIIA Redox Reactions Example of Metal and Non-Metal Reaction: 2 Na + Cl 2 2 NaCl + energy LEO GER DEMO Redox Reactions Reactants transfer electrons. Reactants change charge (oxidation state). 2 Na (s) + Cl 2 (g) 2 NaCl (s) Lose of e s = oxidation (Na Na + in NaCl) Gain of e s = reduction (Cl Cl - in NaCl)
REDOX alf Reactions Oxidation Reduction ( > in oxidation state) ( < in oxidation state) 2 ( Na Na+ + e- ) ( Cl 2 + 2e- 2Cl ) - alf rxns always written to show electron GAIN. The equation = the sum of the half reactions where electrons lost = electrons gained: 2 Na + Cl 2 2 Na + + 2 Cl - OXIDIZING AGENT Gains electrons and is reduced (GER) REDUCING AGENT Loses electrons and is oxidized (LEO) Oxidizing agents cause the oxidation of other substances. Reducing agents cause the reduction of other substance. Redox Agents Q. Label the reducing agent (RA) and oxidizing agent (OA) in the reaction: 2 Na + Cl 2 2 Na + + 2 Cl - + energy The stronger RA and OA = reactants The reactants exchange electrons spontaneously; energy is released The weaker RA and OA products do not exchange electrons
Redox Agents Q. Based on the reaction below between Na and Cl 2, compare sodium metal and chloride ion as reducing agents (RA) 2 Na + Cl 2 2 Na + + 2 Cl - + energy a) Cl - > Na b) Na > Cl - c) Cl 2 > Na + d) Na + > Cl - Redox Agents Q. Based on the reaction below between Na and Cl 2, rank the oxidizing agents (OA) 2 Na + Cl 2 2 Na + + 2 Cl - + energy Answer: > Note that the metal Na = RA but its metal ion Na + = OA 1A VIIIA 1 2 e 1s 1 IIA IIIA IVA VA VIA VIIA 1s 2 3 Li 4 Be 5 B 6 C 7 N 8 O 9 F 10 Ne 2s 1 2s 2 2s 2 2p 1 2s 2 2p 2 2s 2 2p 3 2s 2 2p 4 2s 2 2p 5 2s 2 2p 6 11 Na 3s 1 19 K 4s 1 37 Rb 5s 1 55 Cs 6s 1 87 Fr 7s 1 12 Mg 13 Al 14 Si 15 P 16 S 17 Cl 18 Ar 3s 2 IIIB IVB VB VIB VIIBVIIIB VIIIB IB IIB 3s 2 3p 1 3s 2 3p 2 3s 2 3p 3 3s 2 3p 4 3s 2 3p 5 3s 2 3p 6 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 4s 2 3d 1 4s 2 3d 2 4s 2 3d 3 4s 2 3d 5 4s 1 3d 5 4s 2 3d 6 4s 2 3d 7 4s 2 3d 8 4s 2 4s 2 4p 1 4s 2 4p 2 4s 2 4p 3 4s 2 4p 4 4s 2 4p 5 4s 2 4p 6 3d 10 4s 1 3d 10 4s 2 38 Sr 5s 2 56 Ba 6s 2 88 Ra 7s 2 39 40 41 42 43 44 45 46 Y Zr Nb Mo Tc Ru Rh Pd 4d 1 5s 2 4d 2 5s 2 4d 3 5s 2 4d 5 5s 1 4d 5 5s 2 4d 7 5s 1 4d 8 5s 1 4d 10 57 La* 5d 1 6s 2 Background Information: Redox Metals = reducing agents (LEO) Metal ions IA and IIA = oxidizing agents (GER) Other Metal ions = oxidizing or reducing agents 47 Ag 4d 10 5s 1 48 Cd 4d 10 5s 2 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe 5s 5p 1 5s 5p 2 5s 5p 3 5s 5p 4 5s 2 5p 5 5s 5p 6 72 f 73 Ta 74 W 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 g 81 Tl 82 83 Bi 84 Po 85 At 86 Rn 5d 2 6s 2 5d 3 6s 2 5d 4 6s 2 5d 5 6s 2 5d 6 6s 2 5d 7 6s 2 5d 9 6s 1 6s 2 6p 1 6s 2 6p 2 6s 2 6p 3 6s 2 6p 4 6s 2 6p 5 6s 2 6p 6 5d 10 6s 1 5d 10 6s 2 89 104 105 106 107 108 109 + Element synthesized, Ac # + + + + + + but no official name assigned 6d 1 7s 2 6d 2 7s 2 6d 3 7s 2 6d 4 7s 2 6d 5 7s 2 6d 6 7s 2 6d 7 7s 2
Multiple oxidation state metal ions Some metal ions can act as an oxidizing or reducing agent! Example: Sn = 0, 2+ and 4+ Sn 2+ ion can gain electrons = OA: Sn 2+ + 2 e- Sn Sn 2+ ion can lose electrons = RA: Sn 2+ Sn 4+ + 2 e- Predicting Redox Strength Electronegativity and Redox Strength Electronegativity and Redox Strength Electronegativity values (p.222, manual) reflect an elements attraction for electrons when forming a bond 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2.1 Li Be B C N O F 1.0 2.0 2.5 3.0 3.5 4.0 Na Mg Al Si P S Cl 0.9 1.2 2.1 2.5 3.0 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br 0.8 1.0 1.3 1.6 1.6 1.6 1.6 2.0 2.4 2.8 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I 0.8 1.0 1.2 1.4 1.6 1.7 1.7 2.1 2.5 Cs Ba La f Ta W Re Os 0.7 0.9 -Lu 1.3 1.7 Fr Ra Ac Th Pa U Np- No 0.7 0.9 1.1 1.3 1.7 1.3 Ir Pt Au 2.4 g Tl Bi Po 2.0 At
IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2.1 Li 1.0 Q. Where are the best reducing agents located in the electronegativity table? Be Na Mg 0.9 1.2 K Ca Sc Ti V Cr Mn Fe Co 0.8 1.0 1.3 1.6 1.6 Rb Sr Y Zr Nb Mo Tc Ru Rh 0.8 1.0 1.2 1.4 1.6 Cs Ba La f Ta W Re Os Ir 0.7 0.9 -Lu 1.3 1.7 Fr Ra Ac Th Pa U Np- No 0.7 0.9 1.1 1.3 1.7 1.3 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Al Si P S Cl 2.1 2.5 3.0 Ni Cu Zn Ga Ge As Se Br 1.6 1.6 2.0 2.4 2.8 Pd Ag Cd In Sn Sb Te I 1.7 1.7 2.1 2.5 Pt Au g Tl Bi Po At 2.4 2.0 IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2.1 Li 1.0 Q. Where are the best oxidizing agents located in the electronegativity table? Be Na Mg 0.9 1.2 K Ca Sc Ti V Cr Mn Fe Co 0.8 1.0 1.3 1.6 1.6 Rb Sr Y Zr Nb Mo Tc Ru Rh 0.8 1.0 1.2 1.4 1.6 Cs Ba La f Ta W Re Os Ir 0.7 0.9 -Lu 1.3 1.7 Fr Ra Ac Th Pa U Np- No 0.7 0.9 1.1 1.3 1.7 1.3 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Al Si P S Cl 2.1 2.5 3.0 Ni Cu Zn Ga Ge As Se Br 1.6 1.6 2.0 2.4 2.8 Pd Ag Cd In Sn Sb Te I 1.7 1.7 2.1 2.5 Pt Au g Tl Bi Po At 2.4 2.0 Part IA. Metal reactions with water Rank the reducing agent strength of the metals Na, K, Mg, and Ca from experimental observations. Correlate reactivity results with the position of the metal in the periodic table.
IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2.1 Li 1.0 Q. Predict the RA strength of Mg and Ca based on position and electronegativity values. Be Na Mg 0.9 1.2 K Ca Sc Ti V Cr Mn Fe Co 0.8 1.0 1.3 1.6 1.6 Rb Sr Y Zr Nb Mo Tc Ru Rh 0.8 1.0 1.2 1.4 1.6 Cs Ba La f Ta W Re Os Ir 0.7 0.9 -Lu 1.3 1.7 Fr Ra Ac Th Pa U Np- No 0.7 0.9 1.1 1.3 1.7 1.3 > B C N O F 2.0 2.5 3.0 3.5 4.0 Al Si P S Cl 2.1 2.5 3.0 Ni Cu Zn Ga Ge As Se Br 1.6 1.6 2.0 2.4 2.8 Pd Ag Cd In Sn Sb Te I 1.7 1.7 2.1 2.5 Pt Au g Tl Bi Po At 2.4 2.0 Experimental Comparison of Ca and Mg Metal + Water metal hydroxide + 2 (g) RA OA OA RA Example: Mg(s) + 2O(l) Mg(O) 2 (s) + 2 (g) DEMO RA: Experimental Comparison of Ca and Mg
Q. Predict the RA strength of K and Na compared to Mg, and Ca based on electronegativity values. IA IIA IIIB IVB VB VIB VIIB VIIIB IB IIB IIIA IVA VA VIA VIIA 2.1 Li 1.0 Be B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Na Mg Al Si P S Cl 0.9 1.2 2.1 2.5 3.0 K 0.8 Ca 1.0 Sc 1.3 Ti V 1.6 Cr 1.6 Mn Fe Co Ni Cu Zn 1.6 Ga 1.6 Ge As 2.0 Se 2.4 Br 2.8 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I 0.8 Cs 0.7 Fr 0.7 1.0 Ba 0.9 Ra 0.9 1.2 1.4 La f -Lu 1.3 Ac Th 1.1 1.3 1.6 Ta Pa W 1.7 U 1.7 Re Os Np- No 1.3 > > > Ir Pt Au 2.4 1.7 g 1.7 Tl Bi 2.1 Po 2.0 2.5 At Reactivity of K and Na Experimental determination of the reactivity of K and Na compared to Ca and Mg. DEMO Part I B. Predicting Metal Reactivity. Experimentally determine the comparative reducing agent (RA) strength of four team assigned metals Information: Only three of the four metals will be provided Four of the assigned metal s ions are available
Part 1B Experiment Design Example You need to determine the reducing agent strength of, Cu, and Ag. Available: Solutions of metal ions 2+, Cu 2+, Ag + in the form of 0.10 M metal ion nitrate salts Cu and Ag only (i.e., is unavailable) Table Design for Part 1B. Create a table for recording data (pre-lab). Ag Cu Ag + Cu 2+ 2+ Reducing agents (metals) on one side and oxidizing agents (metal ions) on other side. Part 1B experiment Combine different available metals and metal ions (0.10 M metal ion nitrates) Ag + Cu 2+ 2+ Ag NO Cu NO NO
Metal and Metal ion reactions Cu(s) + AgNO 3 (aq)? Ag(s) + Cu(NO 3 ) 2 (aq)? DEMO Q. Based on experiment results, rank: -The oxidizing agents (Ag + and Cu 2+ ) - The reducing agents (Ag and Cu) OA: > RA: > Cu(s) + Ag + (aq) YES Ag(s) + Cu 2+ (aq) NO
Part 1B experiment Enter results into Part 1B Table Test remaining available metal - metal ion combinations Ag + Cu 2+ 2+ Ag NO NO Cu YES NO NO Metal and Metal ion reactions Cu(s) + (NO 3 ) 2 (aq)? Ag(s) + (NO 3 ) 2 (aq)? DEMO Part 1B experiment Enter results into Part 1B Table Ag + Cu 2+ 2+ Ag NO NO NO Cu YES NO NO NO
Q. Complete the table below and indicate the comparative RA strength of Ag, Cu, and. Ag + Cu 2+ 2+ Ag NO NO NO Cu YES NO NO NO RA strength: Questions? Contact nkerner@umich.edu