The molecule in which hybrid $MOs$ involve only one $d-$orbital of the central atom is:

$[FeF_6]^{3-}$ has ........ hybridisation and ....... geometry. Select the best option to fill the blank space respectively:

Give the correct sequence of initials $T$ or $F$ for the following statements. Use $T$ if the statement is true and $F$ if it is false.
$(I) \ Co(III)$ is stabilized in the presence of weak field ligands,while $Co(II)$ is stabilized in the presence of strong field ligands.
$(II)$ Four-coordinated complexes of $Pd(II)$ and $Pt(II)$ are diamagnetic and square planar.
$(III) \ [Ni(CN)_4]^{4-}$ ion and $[Ni(CO)_4]$ are diamagnetic tetrahedral and square planar respectively.
$(IV) \ Ni^{2+}$ ion does not form inner orbital octahedral complexes.

In the complex $cis-[Cr(en)_2Cl_2]^+$,the oxidation state of $Cr$,the type of $d$-orbital involved in the valence shell,and the coordination number are respectively:

Which of the following is/are correct for the complex $[Cu(NH_3)_4]^{2+}$?

The total number of unpaired electrons present in $[Co(NH_3)_6]Cl_2$ and $[Co(NH_3)_6]Cl_3$ is $......$