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Delocalisation & Resonance The delocalisation of electrons can explain the structures of some species that don’t seem to fit with a Lewis structure Delocalised electrons are electrons in a mole...
Formal Charge A limitation of the model of covalent bonding is that when drawing Lewis structures for molecules, it is sometimes possible to come up with more than one structure while still obeying...
Further VSEPR Theory Revisiting Valence Shell Electron Pair Repulsion Theory (VSEPR) When an atom forms a covalent bond with another atom, the electrons in the different bonds and the non-bonding e...
Octet Rule Exceptions Incomplete octets We have seen previously that for elements below atomic number 20 the octet rule states that the atoms try to achieve 8 electrons in their valence shells, so ...
Sigma Bonds Bond overlap in covalent bonds A single covalent bond is formed when two nonmetals combine Each atom that combines has an atomic orbital containing a single unpaired electron When a cov...
Factors Affecting Colour The size of the splitting energy ΔE in the d-orbitals is influenced by the following four factors: The size and type of ligands The nuclear charge and identity of the metal...
Crystal Field Theory Perception of colour Most transition metal compounds appear coloured. This is because they absorb energy corresponding to certain parts of the visible electromagnetic spectrum ...
Catalytic Properties Transition metals are often used as catalysts in the elemental form or as compounds The ability of transition metals to form more than one stable oxidation state means that the...
Complex Ions Transition element ions can form complexes which consist of a central metal ion and ligands A ligand is a molecule or ion that forms a co-ordinate bond with a transition metal by donat...
