electronic configuration no. of unpaired electrons 
∴ Since Co2+ has lowest no. of unpaired electrons hence lowest paramagnetic behaviour is shown by [Co(H2O)6]2+
JEE Main 2012 — Chemistry Inorganic Chemistry
The d-electron configurations of Cr2+,Mn2+,Fe2+ and Co2+ are d4,d5,d6 and d7 respectively. Which one of the following will exhibit the lowest paramagnetic behaviour? (Atomic no. Cr=24,Mn=25,Fe=26,Co=27 ).
Held on 7 May 2012 · Verified 6 Jul 2026.
[Co(H2O)6]2+
[Cr(H2O)6]2+
[Mn(H2O)6]2+
[Fe(H2O)6]2+
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