What will be the type of hybridization if the shapes are square planar,octahedral,and linear,respectively?

The geometry and magnetic property of $[NiCl_4]^{2-}$,respectively are

What is the coordination number of the central metal ion if it forms an octahedral complex?

What is the coordination geometry around the manganese atom in decacarbonyldimanganese$(0)$?

$[NiCl_{4}]^{2-}$ is paramagnetic while $[Ni(CO)_{4}]$ is diamagnetic though both are tetrahedral. Why?

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.