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 2.2.1d)

Learners should use sub-shell notation e.g. for Fe: 1s²2s²2p⁶3s²3p⁶3d⁶4s².

the elements Ti–Cu as transition elements i.e. d-block elements that have an ion with an incomplete d-sub-shell

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 5.3.1k)
(ii) the formation of coloured ions (see also 5.3.1h, j–k)
(iii) the catalytic behaviour of the elements and their compounds and their importance in the manufacture of chemicals by industry (see 3.2.2d)

No detail of how colour arises required.
Practical examples of catalytic behaviour include: Cu²⁺ for reaction of Zn with acids; MnO₂ for decomposition of H₂O₂.
No detail of catalytic processes required.

explanation and use of the term ligand in terms of coordinate (dative covalent) bonding to a metal ion or metal, including bidentate ligands

Examples should include:
monodentate: H₂O, Cl^– and NH3
bidentate: NH₂CH₂CH₂NH₂ (‘en’).
In exams, other ligands could be introduced.

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 2.2.2g–h)

Examples:
Octahedral: many hexaaqua complexes, e.g. [Cu(H₂O)₆]²⁺, [Fe(H₂O)₆]³⁺
Tetrahedral: many tetrachloro complexes, e.g. CuCl₄^2– and CoCl₄^2–
Square planar: complexes of Pt, e.g. platin: Pt(NH₃)₂Cl₂ (see also 5.3.1g).

types of stereoisomerism shown by complexes, including those associated with bidentate and multidentate ligands:

(i) cis–trans isomerism e.g. Pt(NH₃)₂Cl₂ (see also 4.1.3c–d)
(ii) optical isomerism e.g. [Ni(NH₂CH₂CH₂NH₂)₃]²⁺ (see also 6.2.2c)

Learners should be able to draw 3-D diagrams to illustrate stereoisomerism.

use of cis-platin as an anti-cancer drug and its action by binding to DNA preventing cell division

ligand substitution reactions and the accompanying colour changes in the formation of:

(i) [Cu(NH₃)₄(H₂O)₂]²⁺ and [CuCl₄]^2– from [Cu(H₂O)₆]²⁺
(ii) [Cr(NH₃)₆]³⁺ from [Cr(H₂O)₆]³⁺ (see also 5.3.1j)

Complexed formulae should be used in ligand substitution equations.

explanation of the biochemical importance of iron in haemoglobin, including ligand substitution involving O₂ and CO

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

For precipitation, non-complexed formulae or complexed formulae, are acceptable e.g. Cu²⁺(aq) or [Cu(H₂O)6]²⁺; Cu(OH)₂(s) or Cu(OH)₂(H₂O)₄.
With excess NaOH, only Cr(OH)₃ reacts further forming [Cr(OH)₆]^3–.
With excess NH₃, only Cr(OH)₃ and Cu(OH)₂ react forming [Cr(NH₃)₆]³⁺ and [Cu(NH₃)₄(H₂O)₂]²⁺ respectively (see also 5.3.1h).

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

Fe²⁺ can be oxidised with H⁺/MnO₄^– and Fe³⁺ reduced with I^–, Cr³⁺ can be oxidised with H₂O₂/OH^– and Cr₂O₇^2– reduced with Zn/H⁺, Cu²⁺ can be reduced with I^–. In aqueous conditions, Cu⁺ readily disproportionates.  
Learners will not be required to recall equations but may be required to construct and interpret redox equations using relevant half-equations and oxidation numbers (see 5.2.3b–c).

interpretation and prediction of unfamiliar reactions including ligand substitution, precipitation, redox.