Worksheet 5 Inorganic_4e5490df455df922c2183bf55f8c88a6.pdf

CHM1206 Worksheet 5 (Inorganic) – Transition metals and Coordination Compounds N.B. Familiarise yourself with the uses of transition elements and their compounds. Exercises for naming complexes and writing formulae are on the handout “Naming complex compounds”. 1. Define the following terms: transit...

CHM1206 Worksheet 5 (Inorganic) – Transition metals and Coordination Compounds N.B. Familiarise yourself with the uses of transition elements and their compounds. Exercises for naming complexes and writing formulae are on the handout “Naming complex compounds”. 1. Define the following terms: transition elements bidentate lanthanide contraction coordination compounds tetradentate hexadentate polydentate ligand coordinate (or dative) covalent bond 2. Give the electronic configuration for each of the following ions: a) Cr3+ c) Ni2+ b) V2+ d) Cu+ 3. Match up the isoelectronic ions (those with the same number of electrons) on the following list: Cu+ Mn2+ Fe2+ Co3+ Fe3+ Zn2+ Ti2+ V3+ 4. Study the ionisation energy table below and answer the question that follows: Ionisation energies (kJ/mol) Element First Second Third Fourth Fe 759 1561 2957 --Ti 658 1310 2652 4175 The ore ilmenite has a formula FeTiO3. Use the ionisation energies above to decide whether ilmenite is composed of Fe2+ and Ti4+ ions or Fe3+ and Ti3+ ions. 5. Why is vanadium (density 6.11 g/cm3) much less dense than chromium (7.19 g/cm3). Both metals have a body-centred cubic crystal lattice. 6. Of the following pairs, which has the larger: i) atomic radius: vanadium and titanium; iron and chromium ii) first ionisation energy: iron and nickel; nickel and copper; manganese and cobalt 7. Of V, Cr and Mn, which would you expect to form an oxide with the formula MO3? Explain your answer. 1 8. Give the oxidation number of the metal ion (or atom) in each of the following complexes: a) [Mn(NH3)6]SO4 d) [Fe(NH3)6]2+ b) K3[Co(CN)6] e) [Zn(CN)4]2- c) [Co(NH3)4Cl2]Cl f) [Co(NH3)5NO2]+ 9. What must a ligand have in order to bond to a metal? What is meant by the term “coordinate covalent bond”? 10. Determine the coordination numbers and predict the geometries of the following complex species: a) [Ir(en)3]3+ c) [PtCl2(NH3)2] b) [Fe(ox)3]3- d) Fe(CO)5 11. Two chemists prepared a complex and determined its formula which they wrote as [CrCl3NH3].2H2O. However, when they dissolved 2.11 g of the compound in water and added an excess of AgNO3, 2.87 g of AgCl precipitated and they realised that the formula was incorrect. Write the correct formula and draw its structure. 12. A solid pink salt has the formula CoCl3.5NH3.H2O. When AgNO3 (MM 169.87 g/mol) is added to an aqueous solution containing 0.0010 mol of the salt, 0.43 g of AgCl (143.32 g/mol) precipitated. Heating the salt produces a purple solid with formula CoCl3.5NH3. a) Write the correct formula and name the pink salt, and b) Predict its geometry. *** 2