Assertion (A) : The total number of geometrical isomers shown by [Co(en)2Cl2]+[Co(en)2Cl2]+complex ion is three.Reason (R): [Co(en)2Cl2]+[Co(en)2Cl2]+complex ion has an octahedral geometry.

The assertion (A) is incorrect while the reason (R) is correct.

Step 1: Understanding the complex ion The complex ion [Co(en)2Cl2]+ is a coordination compound where Co is the central metal atom, en (ethylenediamine) is a bidentate ligand, and Cl is a monodentate ligand.

Step 2: Determining the geometry The complex ion has an octahedral geometry because the coordination number of Co is 6 (each en ligand provides 2 sites of attachment and there are 2 Cl ligands).

Step 3: Determining the number of geometrical isomers Geometrical isomers in coordination compounds arise due to the spatial arrangement of ligands. In this complex ion, the two Cl- ligands can either be adjacent to each other (cis-isomer) or opposite to each other (trans-isomer). However, due to the presence of the bidentate ligand (en), there is no possibility of having a cis-isomer because the two nitrogen atoms of each en ligand must be adjacent to each other. Therefore, the complex ion [Co(en)2Cl2]+ can only exist as a trans-isomer.

So, the total number of geometrical isomers shown by [Co(en)2Cl2]+ complex ion is one, not three as stated in the assertion.