9. Inorganic chemistry - 9.5 An introduction to the chemistry of transition elements

Content

I General physical and characteristic chemical properties of the first set of transition elements, titanium to copper

II Colour of complexes

Learning outcomes

Candidates should be able to:

(a) explain what is meant by a transition element, in terms of d-block elements forming one or more stable ions with incomplete d orbitals

(b) *state the electronic configuration of a first row transition element and of its ions

(c) state that the atomic radii, ionic radii and first ionisation energies of the transition elements are relatively invariant

(d) *contrast, qualitatively, the melting point, density, atomic radius, ionic radius, first ionisation energy and conductivity of the transition elements with those of calcium as a typical s-block element

(e) describe the tendency of transition elements to have variable oxidation states

(f) predict from a given electronic configuration, the likely oxidation states of a transition element

(g) describe and explain the use of Fe3+/Fe2+, MnO4-/Mn2+ and Cr2O72-/Cr3+ as examples of redox systems (see also Section 6)

(h) predict, using E values, the likelihood of redox reactions

(i) *explain the reactions of transition elements with ligands to form complexes, including the complexes of copper(II) ions with water, hydroxide and ammonia

(j) explain qualitatively that ligand exchange may occur, including the complexes of copper(II) ions with water, hydroxide and ammonia

(k) describe the shape and symmetry of the d orbitals, and the splitting of degenerate d orbitals into two energy levels in octahedral complexes using the complexes of copper(II) ions with water and ammonia as examples

(l) explain the origin of colour in transitional element complexes resulting from the absorption of light energy as an electron moves between two non-degenerate d orbitals

(m) describe, in qualitative terms, the effects of different ligands on the absorption, and hence colour, using the complexes of copper(II) ions with water, hydroxide and ammonia as examples

(n) state examples of catalysis by transition metals and/or their compounds, including iron in the Haber process and vanadium in the Contact process