Chem : Feb E3 Redox: Transferring Electrons. E3: Redox: Transferring Electrons

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1 Chem. 5-6: Feb. - 7 Preparation Pre-lab Report (p.90) for E3 completed Discussion Presentation for E completed Pre-lab reading and studies for E3 completed Lab enda One hour discussion of E (Questions, p.73) Two hours of E3; E3= two session 5 hour lab E3: Redox: Transferring Electrons Session : Two our Lab enda* Complete Part Complete Part A Complete Team Report (Parts and A) * See Student formation Sheet on Ctools under Resources Experiments. Session : Three our Lab enda Complete Parts B and 3 E3 Redox: Transferring Electrons Redox = oxidation-reduction Redox reactions involve electron transfer. Loss of electrons (LEO) = oxidation Gain of electrons (GER) = reduction A e s IIA IIIA IVA VA VIA VIIA s B 6 C 7 N 8 O 9 F 0 Ne s s s p s p s p 3 s p 4 s p 5 s p 6 Na 3s 9 4s 37 Rb 5s 55 Cs 6s 7s Mg 3 4 Si 5 P 6 S 7 Cl 8 Ar 3s IIIB IVB VB VIB VIIBVIIIB VIIIB IB IIB 3s 3p 3s 3p 3s 3p 3 3s 3p 4 3s 3p 5 3s 3p Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br r 4s 3d 4s 3d 4s 3d 3 4s 3d 5 4s 3d 5 4s 3d 6 4s 3d 7 4s 3d 8 4s 4s 4p 4s 4p 4s 4p 3 4s 4p 4 4s 4p 5 4s 4p 6 3d 0 4s 3d 0 4s 38 Sr 5s 56 Ba 6s 88 Ra 7s Y Zr Nb Mo Tc Ru Rh Pd 4d 5s 4d 5s 4d 3 5s 4d 5 5s 4d 5 5s 4d 7 5s 4d 8 5s 4d 0 57 La* 5d 6s Background formation: Redox Metals lose electrons (LEO) Non-metals gain electrons GER) 4d 0 5s 4d 0 5s 5 5 Te 53 I 54 Xe 5s 5p 5s 5p 5s 5p 3 5s 5p 4 5s 5p 5 5s 5p 6 7 f 73 Ta 74 W 75 Re 76 Os 77 Ir g At 86 Rn 5d 6s 5d 3 6s 5d 4 6s 5d 5 6s 5d 6 6s 5d 7 6s 5d 9 6s 6s 6p 6s 6p 6s 6p 3 6s 6p 4 6s 6p 5 6s 6p 6 5d 0 6s 5d 0 6s Element synthesized, Ac # but no official name assigned 6d 7s 6d 7s 6d 3 7s 6d 4 7s 6d 5 7s 6d 6 7s 6d 7 7s Q. Max positive oxidation state of family A metal ions? A s IIA 3 4 s s Q. Oxidation states of? VIIA IIIA IVA VA VIA 3 3s 3s VIIIB 9 0 IIIB IVB VB VIB VIIB VIIIB IB IIB 3s 3p Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge 4s 4s 4s 3d 4s 3d 4s 3d 3 4s 3d 5 4s 3d 5 4s 3d 6 4s 3d 7 4s 3d 8 4s 3d 0 4s 3d 0 4s 4p 4s 4p Rb Sr Y Zr Nb Mo Tc Ru Rh Pd 5s 5s 5s 4d 5s 4d 5s 4d 3 5s 4d 5 5s 3d 5 5s 4d 7 5s 4d 8 4d 0 5s 4d 0 5s 4d 0 5s 5p 5s 5p 5s 5p Cs Ba La* f Ta W Re Os Ir g 6s 6s 6s 5d 6s 5d 6s 5d 3 6s 5d 4 6s 4d 5 6s 5d 6 5d 7 6s 6s 5d 9 6s 5d 0 6s 5d 0 6s 6p 6s 6p 6s 6p 3 6s 6p Element synthesized, Ra Ac # 7s 7s 7s 6d 7s 6d 7s 7d 3 7s 6d 4 7s 3d 5 6s 6d 6 6d 7 7s but no official name assigned = 0 or or 4

2 A s IIA 3 4 s s s 3s IIIB IVB VB VIB VIIB VIIIB " VIIIB IB IIB 9 4s 0 Ca 4s Sc 4s 3d Ti V Cr Mn Fe Co Ni Cu 4s 3d 4s 3d 3 4s 3d 5 4s 3d 5 4s 3d 6 4s 3d 7 4s 3d 8 4s 3d Rb Sr Y 40 Zr 4 Nb 4 Mo 43 Tc 44 Ru 45 Rh 46 Pd 5s 5s 5s 4d 5s 4d 5s 4d 3 5s 4d 5 5s 3d 5 5s 4d 7 5s 4d 8 4d 0 55 Cs 6s 7s 56 Ba 6s Transition Metals 5s 4d 0 30 Zn 4s 3d IIIA IVA VA 3 3s 3p 3 Ga 4s 4p 3 Ge 4s 4p 5s 4d 0 5 5s 5p 5s 5p 5s 5p 3 6 VIA La* f Ta W Re Os Ir g 6s 5d 6s 5d 6s 5d 3 6s 5d 6s 4d 6s 5d 6 5d 6s 6s 5d 6s 6p 6s 6p 6s 6p 3 6s 6p s 5d 0 6s 5d Element synthesized, Ra Ac # but no official name assigned 7s 7s 6d 7s 6d 7s 7d 3 7s 6d 4 7s 3d 5 6s 6d 6 6d 7 7s 7 VIIA 8 Q. Maximum oxidation state vs. family #? Redox Reactions Example: Na Cl NaCl energy LEO DEMO GER Redox Reactions Reactants transfer electrons. Reactants change charge (oxidation state). Na (s) Cl (g) 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) ( Na Na e- ) ( Cl e- Cl - ) alf rxns always written to show electron GAIN. The equation = the sum of the half reactions where electrons lost = electrons gained: Na Cl Na Cl - OXIDIZING AGENT Gains electrons and is reduced (GER) REDUCING AGENT Loses electrons and is oxidized (LEO) Q. Label the reducing agent (RA) and oxidizing agent (OA) in the reaction: Na Cl Na Cl - energy Oxidizing agents cause the oxidation of other substances. Reducing agents cause the reduction of other substance.

3 Reducing and Oxidizing ent Strength The stronger RA and OA = reactants The weaker RA and OA = products Na Cl Na Cl - OA strength: Cl > Na Q. Based on the reaction below between Na and Cl, compare sodium metal and chloride ion as reducing agents (RA) Na Cl Na Cl - energy a) Cl - > Na b) Na > Cl - c) Cl > Na d) Na > Cl - A s 3 s Na 3s 9 4s 37 Rb 5s 55 Cs 6s 7s Metal IONS from IA, IIA and IIB = oxidizing agents IIA 4 s Mg 3s 0 Ca 4s 38 Sr 5s 56 Ba 6s 88 Ra 7s IIIB IVB VBVIBVIIBVIII VIIIB IB IIB Sc 3d 4s 39 Y 4d 5s Example: Zn e - Zn Ti V Cr Mn Fe 3d 4s 3d 3 4s 3d 5 4s 3d 5 4s 3d 6 4s Zr Nb Mo Tc Ru 4d 5s 4d 3 5s 4d 5 5s 4d 5 5s 4d 7 5s 7 Co 3d 7 4s 45 Rh 4d 8 5s La* f Ta W Re Os Ir 5d 6s 5d 6s 5d 3 6s 5d 4 6s 5d 5 6s 5d 6 6s 5d 7 6s Ac # 6d 7s 6d 7s 6d 3 7s 6d 4 7s 6d 5 7s 6d 6 7s 6d 7 7s 8 Ni 3d 8 4s 46 Pd 4d d 9 6s 9 Cu 3d 0 4s 4d 0 5s 79 5d 0 6s 30 Zn 3d 0 4s 4d 0 5s 80 g 5d 0 6s e s IIIA IVA VA VIAVIIA B C N O F Ne s p s p s p 3 s p 4 s p 5 s p 6 3 3s 3p 3 Ga 4s 4p 5s 5p 8 6s 6p Element synthesized, but no official name assigned 4 Si 3s 3p 3 Ge 4s 4p 5s 5p 8 6s 6p 5 P 3s 3p 3 33 As 4s 4p 3 5 5s 5p s 6p 3 6 S 3s 3p 4 34 Se 4s 4p 4 5 Te 5s 5p s 6p 4 7 Cl 3s 3p 5 35 Br 4s 4p 5 53 I 5s 5p 5 85 At 6s 6p 5 8 Ar 3s 3p 6 36 r 4s 4p 6 54 Xe 5s 5p 6 86 Rn 6s 6p 6 Metal IONS outside family IA, IIA and IIB with multiple oxidation states = oxidizing or reducing agents 8 A s IIA IIIA IVA VA VIA VIIA 3 4 s s aa 3s 3s VIIIB IIIB IVB VB VIB VIIB " VIIIB IB 9 4s Ca Sc Ti V Cr Mn Fe 4s 4s 3d 4s 3d 4s 3d 3 4s 3d 5 4s 3d 5 4s 3d Rb Sr Y Zr Nb Mo Tc Ru 5s 5s 5s 4d 5s 4d 5s 4d 3 5s 4d 5 5s 3d 5 5s 4d Cs Ba La* f Ta W Re Os 6s 6s 6s 5d 6s 5d 6s 5d 3 6s 5d 4 6s 4d 5 6s 5d 6 7s 88 Ra 7s 89 Ac # 7s 6d 04 7s 6d 05 7s 7d s 6d s 3d s 6d 6 7 Co 4s 3d 7 45 Rh 5s 4d 8 77 Ir 5d 7 6s 09 6d 7 7s 8 Ni 4s 3d 8 46 Pd 4d s 5d 9 9 Cu 4s 3d 0 5s 4d s 5d 0 3 3s IIB 3p 30 Zn 4s 3d 0 5s 4d 0 80 g 6s 5d 0 3 Ga 4s 4p 5s 5p 8 6s 6p Element synthesized, but no official name assigned 3 Ge 4s 4p 5s 5p 8 6s 6p 5 5s 5p s 6p s 6p 4 Multiple oxidation state metal ions Some metal ions can act as an oxidizing or reducing agent Example: = 0, and 4 ion can gain electrons = OA: e- ion can lose electrons = RA: 4 e- Predic'ng Redox Strength Electronega'vity and Redox Strength

4 Electronegativity and Redox Strength Electronegativity values (p., manual) reflect an Q. Where are the best oxidizing agents located in the electronegativity table? elements attraction for electrons when forming a bond..0.5 B.0 C.5 N 3.0 O 3.5 F B C N O F Si P S Cl Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Te I Cs Ba La f Ta W Re Os Lu Ir...4 g At. Na 0.9 Mg. Ca Sc Ti V Cr Mn Fe Rb Sr Y Zr Nb Mo Tc Ru Cs Ba La f Ta W Re Os Lu Si.8 P. S.5 Cl 3.0 Co Ni Cu Zn Ga Ge As Se Br Rh Pd Te I Ir g At Note: The element O is in the area (upper right corner)..0 Q. Where are the best reducing agents located in the electronegativity table? Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu B.0 C.5 N 3.0 O 3.5 F 4.0 Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Te I g At Note: The element Ra is in the area (lower left hand corner) Part IA. Metal reactions with water Rank the reducing agent strength of the metals Na,, Mg, and Ca from experimental observations. Correlate reactivity results with the position of the metal in the periodic table...0 Q. Predict the RA strength of Mg and Ca based on position and electronegativity values Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu > Ca Mg B C N O F Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Te I g At Experimental Comparison of Ca and Mg Metal Water metal hydroxide (g) Example: Mg(s) O(l) Mg(O) (s) (g) DEMO RA: Ca > Mg

5 Q. Predict the RA strength of and Na compared to Mg and Ca based on electronegativity values Ca Sc Ti V Cr Mn Fe Co Rb Sr Y Zr Nb Mo Tc Ru Rh Cs Ba La f Ta W Re Os Ir Lu B C N O F Si P S Cl Ni Cu Zn Ga Ge As Se Br Pd Te I g At > Na > Ca > Mg Reactivity of and Na Experimental determination of the reactivity of and Na compared to Ca and Mg. Experimental Comparison of, Na, Ca, and Mg Part I B. Predicting Metal Reactivity. Experimentally determine the reducing agent (RA) strength of four team assigned metals Na skitters around the water surface RA: > Na > Ca > Mg skitters around the water surface and ignites Theoretical prediction (from electronegativity values) and experimental results agree formation: Only three of the four metals will be provided Four of the assigned metal s ions will be provided Part B Experiment Design Example You need to determine the reducing agent strength of, Cu, and. formation: Solutions of metal ions, Cu, in the form of 0.0 M metal ion nitrate salts Cu and only (i.e., is unavailable) Table Design for Part B. ) Create a table for recording data (pre-lab). Cu Cu Reducing agents (metals) on one side and oxidizing agents (metal ions) on other side.

6 Part B experiment ) Combine different available metals and metal ions (0.0 M metal ion nitrates) Cu NO Cu NO NO Example: Cu versus Cu (s) Cu (aq) versus Cu(s) (aq) Q. Based on experiment results, rank: -The oxidizing agents ( and Cu ) - The reducing agents ( and Cu) OA: > Cu RA: Cu > Metal and Metal Ion Reactions RA: Cu > OA: > Cu Stronger RA and OA = Reactants Cu(s) (aq) YES (s) Cu (aq) NO Cu(s) (aq) (s) Cu (aq) Part B experiment Q. Complete the table below and indicate the comparative RA strength of, Cu, and. 4) Enter all tested available metal/metal ion combo results into Part B Table Cu Cu NO NO NO Cu YES NO NO NO NO NO Cu YES NO NO YES YES NO 0 NO RA strength: > Cu >

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