What is the ionization isomer of $[Cr(H_2O)_4Cl(NO_2)]Cl$?

Total number of cis $N-Mn-Cl$ bond angles (that is,$Mn-N$ and $Mn-Cl$ bonds in cis positions) present in $cis-[Mn(en)_2Cl_2]$ is: $(en = NH_2CH_2CH_2NH_2)$

Which of the following compounds are colourless? ($TiF_6^{2-}, CoF_6^{3-}, Cu_2Cl_2$ and $NiCl_4^{2-}$) (Atomic numbers: $Ti = 22, Co = 27, Cu = 29, Ni = 28$)

How many geometrical isomers are shown by the complex $[Pt(NH_3)(NH_2OH)(H_2O)(Py)]^+$?

The electronic configurations of $Cr^{2+}, Mn^{2+}, Fe^{2+},$ and $Co^{2+}$ are $d^4, d^5, d^6,$ and $d^7$ respectively. Which of the following has the lowest magnetic moment? $[Cr = 24, Mn = 25, Fe = 26, Co = 27]$

Select the correct statement$(s)$ regarding the $[Ni(DMG)_2]$ complex compound.