Paramagnetic coordination compounds contain ........ electrons.

Among $(i)$ $[Cr(en)_{3}]^{3+}$,$(ii)$ $trans-[Cr(en)_{2}Cl_{2}]^{+}$,$(iii)$ $cis-[Cr(en)_{2}Cl_{2}]^{+}$,$(iv)$ $[Co(NH_{3})_{4}Cl_{2}]^{+}$,the optically active complexes are:

Complex $X$ of composition $Cr(H_{2}O)_{6}Cl_{n}$ has a spin-only magnetic moment of $3.83 \ BM$. It reacts with $AgNO_{3}$ and shows geometrical isomerism. The $IUPAC$ nomenclature of $X$ is

Given below are two statements:
Statement $I$: $A$ homoleptic octahedral complex,formed using monodentate ligands,will not show stereoisomerism.
Statement $II$: $cis-$ and $trans-$ platin are heteroleptic complexes of $Pd$.
In the light of the above statements,choose the correct answer from the options given below.

Which of the following ions is paramagnetic?

What is the spin-only magnetic moment value $(BM)$ of a divalent metal ion with atomic number $25$ in its aqueous solution?