Transition Metals and their Chemistry

Transition Metal Characteristics and Complex IonsSign up

know that transition metals are d-block elements that form one or more stable ions with incompletely-filled d-orbitals · be able to deduce the electronic configurations of atoms and ions of the d-block elements of Period 4 (Sc-Zn) given their atomic number and charge (if any) · understand why transition metals show variable oxidation number · know what is meant by the term 'ligand' · understand that dative (coordinate) covalent bonding is involved in the formation of complex ions · know that a complex ion is a central metal ion surrounded by ligands

Colour, Coordination Number and ShapeSign up

know that aqueous solutions of transition metal ions are usually coloured · understand that the colour of aqueous ions, and other complex ions, is a consequence of the splitting of the energy levels of the d-orbitals by ligands · understand why there is a lack of colour in some aqueous ions and other complex ions · understand the meaning of the term 'coordination number' · understand that colour changes in transition metal ions may arise as a result of changes in: (i) oxidation number of the ion; (ii) ligand; (iii) coordination number of the complex · understand that H2O, OH- and NH3 act as monodentate ligands · understand why complexes with six-fold coordination have an octahedral shape, such as those formed by metal ions with H2O, OH- and NH3 as ligands · know that transition metal ions may form tetrahedral complexes with relatively large ions such as Cl- · know that square planar complexes are also formed by transition metal ions and that cis-platin is an example of such a complex which is used in cancer treatment where it is supplied as a single isomer and not in a mixture with the trans form · understand the terms 'bidentate' and 'hexadentate' in relation to ligands, and be able to identify examples such as NH2CH2CH2NH2 and EDTA^4- · know that haemoglobin is an iron(II) complex containing a polydentate ligand and that ligand exchange occurs when an oxygen molecule bound to haemoglobin is replaced by a carbon monoxide molecule (the structure of the haem group will not be assessed)

Vanadium and Chromium Redox ChemistrySign up

know the colours of the oxidation states of vanadium (+5, +4, +3 and +2) in its compounds · understand redox reactions for the interconversion of the oxidation states of vanadium (+5, +4, +3 and +2), in terms of the relevant E° values · understand, in terms of the relevant E° values, that the dichromate(VI) ion, Cr2O7^2-, (i) can be reduced to Cr^3+ and Cr^2+ ions using zinc in acidic conditions; (ii) can be produced by the oxidation of Cr^3+ ions using hydrogen peroxide in alkaline conditions (followed by acidification) · know that the dichromate(VI) ion, Cr2O7^2-, can be converted into chromate(VI) ions as a result of the equilibrium Cr2O7^2- + H2O <-> 2CrO4^2- + 2H+

Reactions of Transition Metal Ions and Ligand ExchangeSign up

be able to record observations and write suitable equations for the reactions of Cr^3+(aq), Mn^2+(aq), Fe^2+(aq), Fe^3+(aq), Co^2+(aq), Ni^2+(aq), Cu^2+(aq) and Zn^2+(aq) with aqueous sodium hydroxide and aqueous ammonia, including in excess · be able to write ionic equations to show the meaning of amphoteric behaviour, deprotonation and ligand exchange in the reactions in 17.22 · understand that ligand exchange, and an accompanying colour change, occurs in the formation of: (i) [Cu(NH3)4(H2O)2]^2+ from [Cu(H2O)6]^2+ via Cu(OH)2(H2O)4; (ii) [CuCl4]^2- from [Cu(H2O)6]^2+; (iii) [CoCl4]^2- from [Co(H2O)6]^2+ · understand, in terms of the positive increase in delta S_system, that the substitution of a monodentate ligand by a bidentate or hexadentate ligand leads to a more stable complex ion

Transition Metal CatalysisSign up

know that transition metals and their compounds can act as heterogeneous and homogeneous catalysts · know that a heterogeneous catalyst is in a different phase from the reactants and that the reaction occurs at the surface of the catalyst · understand, in terms of oxidation number, how V2O5 acts as a catalyst in the contact process · understand how a catalytic converter decreases carbon monoxide and nitrogen monoxide emissions from internal combustion engines by: (i) adsorption of CO and NO molecules onto the surface of the catalyst, resulting in the weakening of bonds and chemical reaction; (ii) desorption of CO2 and N2 product molecules from the surface of the catalyst · know that a homogeneous catalyst is in the same phase as the reactants and appreciate that the catalysed reaction will proceed via an intermediate species · understand the role of Fe^2+ ions in catalysing the reaction between I- and S2O8^2- ions · know the role of Mn^2+ ions in autocatalysing the reaction between MnO4^- and C2O4^2- ions · CORE PRACTICAL 14: The preparation of a transition metal complex