How many unpaired electrons will be present in the ground state of an atom which has valence electronic configuration \(3 d^6\) in its +3 oxidation state?

• A

  1
• Correct answer
  B

  3
• C

  4
• D

  7

Solution

Ground state electronic configuration of the element (\(\mathrm{Co}, Z=27)\) will be \([\mathrm{Ar}] 3 d^7 4 s^2\).

Hence, the correct answer is option: 'B'.