Nickel $(Z = 28)$ forms a paramagnetic complex $[NiX_4]^{2-}$ with a uninegative monodentate ligand $X^-$. The number of unpaired electrons in nickel and the geometry of this complex ion are,respectively:

Which of the following complexes is tetrahedral as well as diamagnetic?

Given below are two statements:
Statement $I$: $[Mn(CN)_6]^{3-}$,$[Fe(CN)_6]^{3-}$ and $[Co(C_2O_4)_3]^{3-}$ are $d^2sp^3$ hybridized.
Statement $II$: $[MnCl_6]^{3-}$ and $[FeF_6]^{3-}$ are paramagnetic and have $4$ and $5$ unpaired electrons,respectively.
In the light of the above statements,choose the correct answer from the options given below:

The geometry and magnetic behaviour of the complex $[Ni(CO)_4]$ are

In the tetrahedral complex $K_2[NiCl_4]$,what is the number of electrons present in the $3d$ orbital of the central metal ion?

Which of the following metal carbonyl complexes is correctly matched with its magnetic property and geometry?