For a transition metal with a $d^7$ configuration,the magnetic susceptibility (magnetic moment) is ........ $B.M.$

The electronic configurations of $Cr^{2+}$,$Mn^{2+}$,$Fe^{2+}$,and $Co^{2+}$ ions are $d^4$,$d^5$,$d^6$,and $d^7$ respectively. Which of the following complexes has the minimum paramagnetic character?

Which of the following pairs of isomers and their types of isomerism are correct? Select the correct option.
$(1)\ [Co(NH_3)_5(NO_2)]Cl_2$ and $[Co(NH_3)_5(ONO)]Cl_2$: Linkage isomerism
$(2)\ [Cu(NH_3)_4][PtCl_4]$ and $[Pt(NH_3)_4][CuCl_4]$: Coordination isomerism
$(3)\ [Pt(NH_3)_4Cl_2]Br_2$ and $[Pt(NH_3)_4Br_2]Cl_2$: Ionization isomerism

Consider the following isomerism:
$i$. Ionization
$ii$. Hydrate
$iii$. Coordination
$iv$. Geometrical
$v$. Optical
Which of the above isomerisms are exhibited by $[Cr(NH_3)_2(OH)_2Cl_2]^-$?

The magnitude of magnetic moment (spin only) of $[NiCl_4]^{2-}$ will be ........ $B.M.$

Among the following complexes,the total number of diamagnetic species is. . . . $[Mn(NH_3)_6]^{3+}, [MnCl_6]^{3-}, [FeF_6]^{3-}, [CoF_6]^{3-}, [Fe(NH_3)_6]^{3+}$ and $[Co(en)_3]^{3+}$
[Given,atomic number: $Mn=25, Fe=26, Co=27$; $en=H_2NCH_2CH_2NH_2$ ]