Properties
(a) the electron configuration of atoms and ions of the d-block elements of Period 4 (Sc–Zn), given the atomic number and charge (see also 2.2.1 d)
​
(b) the elements Ti–Cu as transition elements i.e. d-block elements that have an ion with an incomplete d-sub-shell
​
(c) illustration, using at least two transition elements, of:
(i) the existence of more than one oxidation state for each element in its compounds (see also 5.3.1 k)
(ii) the formation of coloured ions (see also 5.3.1 h, j–k)
(iii) the catalytic behaviour of the elements and their compounds and their importance in the manufacture of chemicals by industry (see 3.2.2 d)
Ligands and complex ions
(d) explanation and use of the term ligand in terms of coordinate (dative covalent) bonding to a metal ion or metal, including bidentate ligands
​
(e) use of the terms complex ion and coordination number and examples of complexes with:
(i) six-fold coordination with an octahedral shape
(ii) four-fold coordination with either a planar or tetrahedral shape (see also 2.2.2 g–h)
(f) types of stereoisomerism shown by complexes, including those associated with bidentate and multidentate ligands:
(i) cis–trans isomerism e.g. Pt(NH3) 2Cl 2 (see also 4.1.3 c–d)
(ii) optical isomerism e.g. [Ni(NH2CH2CH2NH2) 3] 2+ (see also 6.2.2 c)
​
(g) use of cis-platin as an anti-cancer drug and its action by binding to DNA preventing cell division
Ligand substitution
(h) ligand substitution reactions and the accompanying colour changes in the formation of:
(i) [Cu(NH3) 4(H2O)2] 2+ and [CuCl 4] 2– from [Cu(H2O)6] 2+
(ii) [Cr(NH3) 6] 3+ from [Cr(H2O)6] 3+ (see also 5.3.1 j)
​
(i) explanation of the biochemical importance of iron in haemoglobin, including ligand substitution involving O2 and CO
Precipitation reactions
(j) reactions, including ionic equations, and the accompanying colour changes of aqueous Cu2+, Fe2+, Fe3+, Mn2+ and Cr3+ with aqueous sodium hydroxide and aqueous ammonia, including:
(i) precipitation reactions
(ii) complex formation with excess aqueous sodium hydroxide and aqueous ammonia
​
(k) redox reactions and accompanying colour changes for:
(i) interconversions between Fe2+ and Fe3+
(ii) interconversions between Cr3+ and Cr2O7 2–
(iii) reduction of Cu2+ to Cu+ and disproportionation of Cu+ to Cu2+ and Cu
​
(l) interpretation and prediction of unfamiliar reactions including ligand substitution, precipitation, redox.