How many geometrical isomers are possible for $[Pd^{2+} (NH_2-CH(CH_3)-CO_2^-)_2]$?

Among the species given below,the total number of diamagnetic species is. . . . . $H$ atom,$NO_2$ monomer,$O_2^{-}$ (superoxide),dimeric sulphur in vapour phase,$Mn_3O_4$,$(NH_4)_2[FeCl_4]$,$(NH_4)_2[NiCl_4]$,$K_2MnO_4$,$K_2CrO_4$

Identify the homoleptic complexes with an odd number of $d$ electrons in the central metal ion.
$(A) \ [FeO_4]^{2-}$
$(B) \ [Fe(CN)_6]^{3-}$
$(C) \ [Fe(CN)_5 NO]^{2-}$
$(D) \ [CoCl_4]^{2-}$
$(E) \ [Co(H_2O)_3 F_3]$
Choose the correct answer from the options given below $:$

The metal atom present in the complex $MABXL$ (where $A, B, X$ and $L$ are unidentate ligands and $M$ is metal) involves $sp^3$ hybridization. The number of geometrical isomers exhibited by the complex is:

Although $Cr^{3+}$ and $Co^{2+}$ ions have the same number of unpaired electrons,why is the magnetic moment of $Cr^{3+}$ $3.87 \ B.M.$ and that of $Co^{2+}$ $4.87 \ B.M.?$

Which of the following compounds does not exhibit paramagnetism?