Give the correct of initials $T$ or $F$ for following statements. Use $T$ if statement is true and $F$ if it is false.
$(I)\, Co(III)$ is stabilised in presence of weak field ligands, while $Co(II)$ is stabilised in presence of strong field ligand.
$(II)$ 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.