The number of isoelectronic species among Sc ^ 3+ , Cr ^ 2+ , Mn ^ 3+ , Co ^ 3+ and Fe ^ 3+ is ' n ^ . If ' n ^ moles of AgCl is formed during the reaction of complex with formula CoCl _ 3 ( en )_ 2 NH _ 3 with excess of AgNO _ 3 solution, then the number of electrons present in the t_ 2 g orbital of the complex is \_\_\_\_.
A. A
For the complex CoCl₃(en)₂NH₃, cobalt is in +3 oxidation state with electron configuration [Ar]3d⁶. In an octahedral field with strong field ligands (ethylenediamine, ammonia, chloride), Co³⁺ forms a low-spin complex with t_ 2g ^6 e_g^0 configuration. The t_ 2g orbitals consist of d_ xy , d_ xz , and d_ yz . With all 6 electrons filling the three t_ 2g orbitals, the total number of electrons in the t_ 2g orbital set is 6.
Related: Chemistry — Coordination Compounds · All PYQ Banks