In this module simple models of bonding in small molecules and complexes are introduced and discussed in terms of the influence of bonding on structure. The background to the periodic table, its structure, and its use in the analysis of trends in elemental properties are reviewed.

1. understand the nature of atomic structure and work out electronic configurations;
2. understand the origins of trends within the periodic table;
3. reproduce and understand MO diagrams for homonuclear diatomics (s- and p-block);
4. understand and use MO diagrams to predict paramagnetism/diamagetism and bond order of diatomics;
5. appreciate the reasons for the differing strengths of chemical bonds;
6. define electronegativity, and explain how it is estimated;
7. summarise and illustrate the chemistry of the elements of Groups 1 and 17;
8. state the key features of the chemistry of the d-block elements
9. understand the various classes of ligand and how they coordinate to metal centres;
10. explain the distinction between hard and soft Lewis acids and bases;
11. understand the factors affecting the thermodynamic stability of complexes;
12. outline the use of crystal field theory in interpreting simple spectroscopic, magnetic, structural and thermodynamic properties of transition metal complexes.

33 1-hour lectures, 30 (10 x 3) hours of practical work, 4 1-hour tutorials

On completion of the module, a student will be able to:

1. use learnt periodic trends to predict differences in properties between related compounds;
2. use the principles of VSEPR to predict the molecular structure of main group compounds;
3. use electrode potentials to predict the relative stability of oxidation states, and the outcome of redox reactions;
4. manipulate a range of chemicals safely with due account of their hazards, with attention to required safety protocols;
5. prepare simple metal complexes by ligand exchange reactions, and determine composition and purity by quantitative analysis.

Coursework (class tests or workshops) and a written exam in May/June will test the student’s knowledge, understanding, and intellectual skills, as elaborated under most of the learning outcomes. Practical work will additionally allow the student to demonstrate his/her ability to judge and critically review relevant information, and allow assessment of the final two learning outcomes.

Atomic and molecular structure

Electronic structure of the atom (qualitative treatment of wavefunctions, hydrogenic atomic orbitals, quantum numbers, many electron atoms, Aufbau principle, Hund’s rules, the Pauli principle, energies of orbitals in many-electron atoms – described in terms of effective nuclear charge, penetration and shielding).

Chemical bonding: covalent vs. ionic vs. metallic bonding vs. H-bonding; Lewis structures, resonance, valence bond theory and its limitations.  Hypervalency in terms of orbital mixing.

MO theory: bonding and antibonding orbitals, energy level diagrams of H₂ and 1^st row diatomics (homo- and heteronuclear).

Introductory periodicity and main group chemistry

The periodic table (link to atomic structure)

Ionisation energy, electron affinity, electronegativity, atomic and ionic radii

Periodic trends in chemical and physical properties of the elements

Bond energies and non-metal chemistry

Lewis acids and Lewis bases (link to coordination chemistry)

Prediction of molecular structure by VSEPR

Chemistry of the s-block elements (Groups 1 & 2): systematic survey; trends based on increasing size and mass; liquid ammonia, crowns and cryptands (link to coordination chemisty)

Introduction to the transition elements and coordination chemistry

Transition element chemistry

Electronic configurations of neutral atoms; dⁿ configurations of cations (and atoms in molecules)

Variation of thermodynamically most stable oxidation state with conditions (cf. main group metals)

Solution equilibria and electrode potentials; ΔG = −nFE; use of electrode potentials to estimate relative stability of oxidation states (Latimer diagrams), outcome of redox reactions; disproportionation

Trends in oxidation state stability across the series and down the groups

Redox equations

Coordination chemistry

The coordinate bond

Nomenclature

Coordination numbers and geometries; isomerism

Classification of ligands: anionic, bidentate, chelates; s- and p-bonding

Stability constants: chelate and macrocyclic effect; Irving-Williams series

HSAB classification

Crystal Field Theory

Crystal field splitting for an octahedral complex, Δ_o the crystal field splitting parameter

Crystal field splitting for a tetrahedral ML₄ complex, Δ_t

High/low-spin e-configurations, spin-only magnetic moment

Spectroscopic consequences of d-orbital splitting: empirical treatment of factors affecting Δ; spectrochemical series

Thermodynamic consequences of d-orbital splitting: contribution of crystal field stabilisation energy to lattice energy, hydration energy, stability constants, etc.

Structural consequences of d-orbital splitting: ionic radii

Ligand field theory, MO description of simple complexes, pi acceptor and donor ligands, trans influence and effect

An indicative reading list will be included in the Course Handbook.