The metal $Ni$ $(Z = 28)$ combines with a unidentate ligand $X^-$ to form a paramagnetic complex $[NiX_4]^{2-}$. What are its geometry and the number of unpaired electrons in $Ni$?

$A$ list of species having the formula $XZ_4$ is given below.
$XeF_4, SF_4, SiF_4, BF_4^-, BrF_4^-, [Cu(NH_3)_4]^{2+}, [FeCl_4]^{2-}, [CoCl_4]^{2-}$ and $[PtCl_4]^{2-}$.
Defining shape on the basis of the location of $X$ and $Z$ atoms,the total number of species having a square planar shape is

Which among the following statements about $[Ni(CN)_4]^{2-}$ is $NOT$ true?

$A$ coordination compound is made of $Co^{3+}$,$NH_3$,and $Cl^{-}$. $A$ $0.1 \ M$ solution of this complex when treated with excess silver nitrate gave no precipitate. The formula of the complex and secondary valency of metal are respectively.

Observe the following complexes: $[Mn(CN)_6]^{3-}, [Fe(CN)_6]^{3-}, [Co(C_2O_4)_3]^{3-}, [MnCl_6]^{3-}, [Fe(CN)_6]^{4-}, [CoF_6]^{3-}$. From the above,the number of inner orbital complexes with paramagnetic nature is

The geometries of some complex ions are given below. Select the correct answer.
$(1) [Ag(NH_3)_2]^+ - \text{Linear}$
$(2) [MnCl_4]^{2-} - \text{Tetrahedral}$
$(3) [Cu(NH_3)_4]^{2+} - \text{Square planar}$
$(4) [Ni(CN)_4]^{2-} - \text{Square planar}$