The Transition metals are located in the middle of the periodic table and have unique chemical properties unlike other metals. D block metals or transition metals as they are commonly known exhibit a number of strange chemical properties. They are able to have variable oxidation states and form complexes. Transition metals are also able to form coloured compounds and act as catalysts. This is primarily down to their unique set of electron orbitals, the d block. D block transition metals have 5 sub-orbitals which allow electrons to occupy a different number of energy levels as the energy levels themselves can split. They are also unique in that they can be occupied in a different number of ways in combination with the 4s sub shell meaning very often compounds have unique colours and properties. One factor to be aware of is that commonly metals with a full D shell like zinc which would have 10 electrons in the d orbital is not considered to be a transition metal due to its full d shell and it forms white compounds.
Transition metals are the central section of the periodic table containing the majority of the metals. Also have d sub orbitals producing certain chemical properties