The main characteristic feature of transition metals is that they

The main characteristic feature of transition metals is that they have variable oxidation states. This means that they can lose or gain different numbers of electrons when they form chemical compounds, allowing them to have a wide range of chemical properties and reactivities. Transition metals are located in the middle of the periodic table and have partially filled d orbitals, which give rise to their unique properties. Their variable oxidation states also make them important catalysts in many chemical reactions, as they can easily switch between different oxidation states to facilitate reactions.