What is the magnetic moment of a divalent ion in aqueous solution if its atomic number is $28$ (in $BM$)?

The correct increasing order of spin-only magnetic moment values of the complex ions $[MnBr_{4}]^{2-}$ $(A)$, $[Cu(H_{2}O)_{6}]^{2+}$ $(B)$, $[Ni(CN)_{4}]^{2-}$ $(C)$ and $[Ni(H_{2}O)_{6}]^{2+}$ $(D)$ is:

Which type of isomerism is exhibited by the square planar complex shown in the image?

Which one of the following pairs of isomers and types of isomerism are correctly matched?
$(i).$ $[Co(NH_3)_5(NO_2)]Cl_2$ and $[Co(NH_3)_5(ONO)]Cl_2$ .... (Linkage)
$(ii).$ $[Cu(NH_3)_4][PtCl_4]$ and $[Pt(NH_3)_4][CuCl_4]$ .... (Coordination)
$(iii).$ $[PtCl_2(NH_3)_4]Br_2$ and $[PtBr_2(NH_3)_4]Cl_2$ .... (Ionization)
Select the correct answer using the codes given below.

Which of the following complexes can exhibit both geometrical and optical isomerism?

Consider the following statements and select the correct option using the codes given.
$(i)$ $[Cr(NH_3)_6][Cr(CN)_6]$ and $[Cr(NH_3)_4(CN)_2][Cr(NH_3)_2(CN)_4]$ are coordination isomers.
$(ii)$ $[Cr(py)_2(H_2O)_2Cl_2]Cl$ and $[Cr(py)_2(H_2O)Cl_3]H_2O$ are linkage isomers.
$(iii)$ $[Pt(NH_3)_4Br_2]Cl_2$ and $[Pt(NH_3)_4Cl_2]Br_2$ are linkage isomers.
$(iv)$ $[NiCl_2(PPh_3)_2]$ (tetrahedral) exhibits geometrical isomerism.