NEETChemistryStructure of Atom
A neutral atom of a 3d transition element possesses an anomalous ground state electronic configuration and has the maximum possible number of unpaired electrons among the elements of its series. What will be the spin-only magnetic moment of its divalent cation?
Options
- A5.92 BM
- B4.90 BM
- C3.87 BM
- D2.83 BM
Correct answer
B. 4.90 BM
Step-by-step solution
The 3d transition element with an anomalous ground state electronic configuration and the maximum number of unpaired electrons is Chromium ( Cr , Z=24 ). Its ground state electronic configuration is [ Ar ] , 4s¹ , 3d⁵ , which has 6 unpaired electrons (the maximum in the 3d series). To form the divalent cation ( Cr ²⁺ ), two electrons are removed. Electrons are removed from the outermost 4s orbital first, followed by the 3d orbital. Configuration of Cr ²⁺ : [ Ar ] , 3d⁴ . The number of unpaired electrons in Cr ²⁺ is