JEE MainChemistryd and f Block Elements
Among the transition metals Ti , V , Mn and Cu , let M be the metal that has the lowest enthalpy of atomisation. The spin-only magnetic moment of the M ²⁺ ion in aqueous solution is closest to
Options
- A1.73 BM
- B2.83 BM
- C5.92 BM
- D4.90 BM
Correct answer
C. 5.92 BM
Step-by-step solution
The standard enthalpies of atomisation for the given metals are approximately: Ti 473 kJ mol ⁻¹ V 515 kJ mol ⁻¹ Mn 281 kJ mol ⁻¹ Cu 339 kJ mol ⁻¹ Among the given choices, Manganese ( Mn ) has the lowest enthalpy of atomisation. This is because its stable half-filled 3 d ⁵ configuration results in weaker interatomic metallic bonding. Thus, metal M is Mn . The ground state electronic configuration of Mn is [ Ar ] 3 d ⁵ 4 s ² . For the divalent ion Mn ²⁺ , the configuration is [ Ar ] 3 d ⁵ . The number of unpaired ele