Coordination Inorganic Chemistry

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Coordination Inorganic Chemistry Practice Exam Coordination Chem Name (last) (irst) Read all questions before you start. Show all work and explain your answers to receive full credit.

1 Coordination Inorganic Chemistry Practice Exam Coordination Chem Name (last) (irst) Read all questions before you start. Show all work and explain your answers to receive full credit. Report all numerical answers to the proper number of significant figures. By signing your signature above you agree that you have worked alone and neither give nor received help from any source. Keep your eyes on your own paper at all times System LENGT: VLUME MASS Temperature English: 1 ft = 12 in 1 gal = 4 qt 1 lb = 16 oz T = 1.8T C mile = 5280 ft 1 qt = in 3 1 ton = 2000 lb 1 yd = 3 ft SI- English: 1 in = 2.54 cm 1 mi = km 1 L = qt 1 qt = L 1 lb = g 1 oz = g T C = (T 32) 1.8 Misc. info 1 mole = R = J/ mol K or L atm/mol K Inorganic: Spectrochemical Series: I - < Br - < Cl - < N 3 - < - < C3 2- < - < 2 < N3 = en < phen < bpy < N2 - < SCN - < CN - < C < ppy Bidentate Ligands f Weak Strong g Color Wheel: phen bpy ppy - 11

2 Multiple -choice. Show work for partial credit. 1 Which of the following chemicals is colorless? a) [Ni(N 3 ) 6 ] + b) [Cu(en) 2 Cl 2 ] c) [Zn () 4 ] 2- d) None 2 Which of the following complexes has a coordination number of 6? a) [Ag(N 3 ) 2 ] + b) [Co(en) 2 Cl 2 ] + c) [Zn (C 3 ) 2 ] 2- d) None. 3 Which of the following complex ion solutions absorbs energy closer to the red end of the color spectrum? a) [MI 6 ] 3- b) [M(en) 3 ] 3+ c) [M(CN) 6 ] 3- d) [M(bpy) 3 ] 3+ 4 Which is the only monodentate ligand? a) C 3 2- b) SCN - c) EDTA d) C Which complex below is not a d 6 specie? a) Na 2 [Mn(EDTA)] b) (N 4 ) 3 [RhCl 6 ] c) K 4 [e(c 2 4 ) 3 ] d) [Ru( 2 ) 6 ](N 3 ) 2 6 Which of the following chemicals has a metal with a +2 oxidation state? a) [Ni(N 3 ) 6 ] Cl 3 b) K[Cu(en) 2 Cl 2 ] c) [Zn () 4 ] 2- d) None 7 Which complex below is the most paramagnetic? a) [Ag(N 3 ) 2 ] + b) [Co(C) 6 ] P 4 c) [e (C 3 ) 3 ] 4- d) None are paramagnetic 8 Which compound below is capable of possessing geometric isomer? Br P t Cl S R h a) Br b) c) d) Br C Br 9 What is the oxidation state of the mercury in[zn(en) 2 ][gi 4 ] a) +1 b) +2 c) +4 d) Cannot be determine 10 Which is the likely structure for the compound, with a titanium +2 metal and iodine ligands? a) Tetrahedral b) Square planar c) ctahedral d) Not enough information

3 11 Name the following coordination, determine the coordination number, and determine whether it is trigonal, tetrahedral, square planar, trigonal bipyramidal or octahedral. i) Na[Co(C 2 4 ) 2 ( 2 ) 2 ] Sodium diaquodioxalatocobaltate(iii) CN = 6, ctahedral ii) [Co( 2 ) 5 Cl]Cl 2 Pentaaquochlorocobalt(III) chloride iii) K[Al(CN) 4 ] Potassium tetracyanoaluminate CN = 6, ctahedral CN = 4, Tetrahedral 12 Define the following: i) Isomers : Same chemical formula but different structural arrangement ii) chelating agent: Ligand that bonds to metal at two sites iii) dextrorotatory: Designation given to an optical isomer that rotates polarized light to the right. 13 Answer the following for the following questions for the structure shown. The chemical formula is: Co 12 6 Cl 3 i) What ligand(s) are in the coordination sphere? Water and chlorides that are shown inside the brackets Co Cl 2 2 ii) What are outside the coordination sphere? Cl Cl and two water shown outside the bracket Cl iii) ow many d-electrons are on the central metal. Cobalt (III), d 6 14 Explain why atomic radii decrease very gradually from scandium to copper. While the valence electrons remain in the same valence shell., Z eff becomes important going across the peiodic table.

4 15 Why do transition metals have more oxidation states than other elements? Transition metals can lose electrons in their d-orbitals allowing them to have a range of oxdation state of +1 to (i) Which chemical between [Cr 6 ] -4 and [W() 6 ] -4 would you expect to have its spin pairing energy (PE) larger than C splitting energy, (Δ)? Explain. [Cr 6 ] -4 has SPE > C splitting energy since Chromium is a smaller atom than tungsten and therefore would have a smaller splitting energy. ii) Which compound between [Cr 6 ] -4 or [W() 6 ] -4 would you expect to absorb longer wavelength of light? Explain. [Cr 6 ] -4 will absorb longer wavelength of light (lower energy) since it has a smaller C splitting energy. (iii) [Cr(2)6] 2+ is violet. Which ligand between CN - and Cl - will give a green CrL6 complex? Explain. [CrCl 6 ] -4 will display a green complex. The complement color of green is red, which is consistent with low energy light absorb which correspond to small C splitting.. (iv) Rank the following complex ions in order of decreasing Δ and energy of visible light absorbed? Explain your choice. [Cr(CN)6] 3- [CoCl6] 3- [Cr(en)3] 3+ Strong ield Ligand, large C splitting Weak ield Ligand, small C splitting Δ (1 ighest) (3 Lowest) (2-Medium) Medium ield Ligand, medium C splitting Energy of light ighest Energy (1 ighest) Lowest Energy (3 Lowest) Medium Energy (2-Medium) 17 (15 pts) Name the following coordination compound, determine the coordination number, determine the number of d- electrons and determine whether it is trigonal, tetrahedral, square planar, trigonal bipyramidal or octahedral. i) Ni(C 2 4 ) 2 (N 3 ) 2 Diaminedioxalato Nickel(IV) CN = 6, d6, ctahedral ii) [Co( 2 ) 5 Cl]Cl 2 Pentaquachloro Cobalt(III) chloride CN = 6, d6, ctahedral iii) K 2 [Pt(CN) 4 ] Potassium tetracyano Platinate(II) CN = 4, d8, Square Planar

18 (9pts) Complete the following statements for the complex ion [Ni Cl (en) 2 N 3 ] S 4 i) The oxidation number of Ni is +3. ii) The coordination number of Ni is 6. iii) The name of the complex is.

ne trans two cis, the cis are enatiomer Enatiomer Pair (Cis isomers) Trans isomer 19 Using CT, diagram the splitting pattern for the following complexes and then describe an experiment to determine

5 18 (9pts) Complete the following statements for the complex ion [Ni Cl (en) 2 N 3 ] S 4 i) The oxidation number of Ni is +3. ii) The coordination number of Ni is 6. iii) The name of the complex is. Amine chloro bis(ethylenediamine) Nickel(III) sulfate iv) Draw all possible isomers for the complex Total of 3 isomers. ne trans two cis, the cis are enatiomer Enatiomer Pair (Cis isomers) Trans isomer 19 Using CT, diagram the splitting pattern for the following complexes and then describe an experiment to determine the following: (Be sure to describe the result of your experiment) (i) Whether the cation in K2[e(CN)6] is a low-spin or a high-spin complex. ere the iron is iron (IV) which means it is d(4) with 4 d-electrons. Since iron is +4, then the splitting is large, and the molecule is most likely lowspin. This means that the molecule has two unpaired electrons. If the molecules were to be high spin, it would have four unpaired electrons. The experiment therefore to test for low-spin or high-spin is to test for the degree of paramagnetism. vs, (ii) Whether nickel in K2[NiCl4] is square-planar or tetrahedral In this complex, the Nickel is +2 or d(8). Almost all d(8) complexes with CN = 4 are square planar. Square planar molecules will have splitting patterns of vs Test for degree of paramagnetism will determine if the complex is square planar or tetrahedral. (iii) Whether a complex has the formula [Co(N3)5Br]C3 or [Co(N3)5(C3)]Br. The complex, [Co(N3)5Br]C3, has coordination complex as a +2 cation. With the Br as a ligand. The complex should have a small splitting relative to the other complex. Treatment of this complex with silver nitrate should show no free halogens. The complex, [Co(N3)5(C3)]Br, has coordination complex as a +2 cation. With the C 3 as a ligand. The complex should have a larger splitting relative to the other complex. Treatment of this complex with silver nitrate should show one free halogens.

20 There are four possible structures (A, B, C and D) for compounds with the general formula [e(en) x ( 2 ) 6-2x ]S 4 where x = 0, 1, 2 or 3 Compounds A and C are paramagnetic and compounds B and D

6 20 There are four possible structures (A, B, C and D) for compounds with the general formula [e(en) x ( 2 ) 6-2x ]S 4 where x = 0, 1, 2 or 3 Compounds A and C are paramagnetic and compounds B and D diamagnetic. Compound B absorbs higher frequency light than compound D. These complexes are highly colored ranging from yellow, orange violet, and green. Assume that the isomers with the same chemical formula all have the same color. Two of these do not have isomers. Compound B can exhibit only optical isomers. Compound D exhibit both optical isomers and geometric isomers. (No coordination isomer is involve) Answer the following questions concerning these four compounds. i) Give the formula, chemical name and molar mass for compounds A, B, C and D. ii) Draw the splitting pattern for compounds A, B, C and D with the d-orbitals labeled and the electrons filled. iii) According to your diagram how many unpaired electron, if any, does each compound possess? iv) Assign the color to each complex. v) Draw the perspective diagram of all compounds (A, B, C and D) and their possible isomers. A [e( 2 ) 6 ]S 4 exaiaquoiron(ii) sulfate B [e(en) 3 ]S 4 Tris(ethylenediamine) Iron(II) sulfate C [e(en)( 2 ) 4 ]S 4 EthylenediaminetetraaquoI ron(ii) sulfate D [e(en) 2 ( 2 ) 2 ]S 4 Bis(ethylenediamine)diaquo Iron(II) sulfate MW = g/mol MW = g/mol MW = g/mol MW = g/mol Absorb: Lowest Energy (Red) Reflect: See as Green Absorb: ighest Energy (Violet) Reflect: See as Yellow Absorb: Second Lowest Energy (range or Yellow) Reflect: See as Violet Absorb: Second ighest Energy (Blue or Green) Reflect: See as range

Coordination compounds

Coordination compounds Multiple choice questions 1. In the complex formation, the central metal atom / ion acts as a) Lewis base b) Bronsted base c) Lewis acid d) Bronsted acid 2. The groups satisfying