IB Inorganic ChemistrySt Anne’s and Oriel Colleges HT 2017

Qualitative Inorganic Chemistry

Suggested reading:

• Chemistry of the Elements, Greenwood & Earnshaw

• Descriptive Inorganic Chemsitry, Rayner-Canham & Overton

• Advanced Inorganic Chemistry, Cotton & Wilkinson

Questions:

(i) Give 1-page outlines showing how you would approach an essay question on each of the fol-

lowing topics (bullet-point format is fine), including key examples you would cite to support

your arguments.

(a) Covalency

(b) Acidity and basicity

(c) Crystal field effects

(d) Metal–metal bonding

(e) The ‘octet’ rule

(ii) For each of the following pairings of elements, give a 1-page outline for a corresponding ‘com-

pare and contrast’ essay. Again, identify key examples you would use to decorate your answer.

(a) H and Au

(b) W and U

(c) B and Si

(iii) For the following series of anions or compounds in the states specified describe the structures

and indicate how this reflects the position of the element in bold in the periodic table. The

formulae may be empirical.

(a) LaCl3(s) AuCl3(s) ReCl3(s)

(b) SnCl2(s) HgCl2(s) GaCl2(s)

(c) [NiCl4]2− [PtCl4]

2− [MoCl4]2−

(d) CO2(g) SiO2(s) PbO2(s)

(e) S4N4(s) BN(s) Li3N(s)

IB Inorganic ChemistrySt Anne’s and Oriel Colleges HT 2017

(iv) Discuss in detail the following data concerning mean bond enthalpies (kJ mol−1) for some

elements E of Group 15, commenting where appropriate on the wider significance of any trends

shown.

N P As

E–E 167 209 180

E≡E 945 493 380

E–H 391 322 297

E–O 214 360 326

E–F 278 490 487

E–Cl 313 322 309

IB Inorganic ChemistrySt Anne’s and Oriel Colleges HT 2017

Past paper questions

(2015 IB Examination—Please answer ALL parts, not just two):

A10499W1 2

1. Compare and contrast the chemistry of the elements in ONE of the following pairs:

N and P Fe and Gd V and Ni Li and Cs [25] 2. Give an account of TWO of the following topics (a) – (f) and their repercussions for the

chemistry of the elements: [2 × 25/2] (a) Lattice energy and the Kapustinskii equation.

(b) The alternation effect.

(c) The empirical rules that describe the structures of boron hydrides.

(d) The electronic radial distribution function.

(e) The Jahn-Teller theorem.

(f) Molecular fluxionality.

3. Comment on points of interest relating to FIVE of the compounds or ions given below. The

chemical formulae, where given, may be empirical. [25] [Ru(bpy)3]2+ MeLi XeF6 Cr(CH3CO2)2(OH2) Mo(CO)6

SmCp2N2 Fe3O4 B5CH6 YBa2Cu3O7-δ carboxypeptidase A

B3N3H6 UO2(NO3)2 PCl5 hemocyanin

[1,3-bis(adamantyl)imidazol-2-ylidene]

4. Write an essay, or structured notes, on ONE of the following topics: [25]

(a) The scope and limitations of the eighteen electron rule.

(b) Structure and bonding in oxo ions of the p-, d- and f- block elements.

(c) Chemical relationships between the chemistry of the elements in groups N and N+10.

(d) The roles of solvent and ligand in coordination chemistry.

(2016 IB Examination):

A10499W1 5

(c) Discuss the variation in the reduction potentials of the Fe3+/Fe2+ and Co3+/Co2+ couples in the presence of the ligands listed in the table below:

Ligand E o(Fe3+/Fe2+) / V E o(Co3+/Co2+) / V

5-NO2-phen +1.25 Not studied

phen +1.10 +0.37

2,3,8,9-Me4-phen +0.85 Not studied

H2O +0.77 +1.94

CN– +0.36 –1.00

oxalate +0.02 +0.57

EDTA4– –0.12 +0.38

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