Question

How do transition elements form coordination compounds?

Answer 1

Due to the presence of partially filled electrons in the d-orbital of the metal the elements are known as transition elements. They are present in the D-block. The main property of transition elements are that they are able to form a coordination complex.

Complete step by step answer:
The transition metal elements are considered as those elements which contain partially filled d orbitals. The transition elements are present in the d-block of the periodic table.
The transition elements can form stable cations due to the presence of unpaired electrons and are paramagnetic in nature. The transition metal forms coordination complexes which are usually colored. The color of the complex is due to the presence of unpaired electrons as the electrons absorb the energy and move to the excited state from the ground state. This is known as d-d transition.
The transition elements and the elements present in the main group can form coordination compounds, or complexes. In the coordination complex the central metal atom is the transition metal cation bonded to one or more ligands by a coordinate covalent bond.
The coordinate covalent bonds are formed when the electrons are shared by only one atom.
In the coordination complex, the central metal atom is Lewis acid and acts as the electron pair acceptor. The ligands are those species which donate the electrons pair. They are considered as Lewis bases and thus act as electron pair donors.
On the basis of the binding site, the ligands are classified as mono-dentate, bi-dentate, tri-dentate, tetra-dentate or polydentate.

Note: You must be clear that transition metals are considered as D-Block elements but all D-block elements are not considered as transition metals.