Most elements in d-block are transition metals
Metals that can form 1 or more stable ions with a partially filled d- sublevel of electrons
All P4 d-block elements are transition metals apart from Sc and Zn
The incomplete D-sublevel causes the chemical properties
Sc is not a transition metal as only forms Sc3+ (empty D-sublevel
Zn only forms Zn2+ (Full D-sublevel)
Transition metals have similar physical properties
High density, high melting and boiling point and ionic radii same
They have special chemical properties
Forms complex ions, coloured ions, catalysts, exists in variable oxidation states
Energy levels of 4s and 3d sub levels are very close. Different electrons gained/ lost using similar amounts of energy
Complex ions
Transition metals form complex ions
A complex is a central metal ion or ion surrounded by co-inordinately bonded Ligands
A co-ordinate bond is a covalent bond where both elections in shared pair from the same atom or ligands in a complex
Ligand - Atom, ion or molecule that forms a co-ordinate bond with a transition metal ion by donating a pair of electrons
The co-ordinate number is the number of coordinate bonds formed with the central metal ion.
Usual co-ordination numbers are 6 and 4.
6 octahedral 90o Smaller ligands i.e. H2O NH3
4 Tetrahedral 109.5 Larger ligands i.e. Cl-
Cisplatin has square planar shape with 4 co-ordinat bonds 90
