Summary
The 3d block contains 10 elements, all of which are metals. Unlike the
metals in Groups 1 and 2, the transition metals Ti to Cu form coloured compounds
and compounds where the transition metal exists in different oxidation states.
Some of these metals are familiar as catalysts. The properties of these
elements are studied in this section with opportunities for a wide range of
practical investigations.
Specification
3.2.5.1
General properties of transition metals
Transition metal characteristics of elements Ti–Cu arise from an
incomplete d sub-level in atoms or ions.
The characteristic properties include:
• complex formation
• formation of coloured ions
• variable oxidation state
• catalytic activity.
A ligand is a molecule or ion that forms a co-ordinate bond with a
transition metal by donating a pair of electrons.
A complex is a central metal atom or ion surrounded by ligands.
Co-ordination number is number of co-ordinate bonds to
the central metal atom or ion.