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The correct order of first ( _i H₁) and second ( _i H₂) ionisation enthalpy values of Cr and Mn are : A. _i H₁ : Cr > Mn B. _i H₂ : Cr > Mn C. _i H₁ : Mn > Cr D. _i H₂ : Mn > Cr Choose the correct answer from the options given below :

Options

  1. AA and B only
  2. BB and C only
  3. CA and D only
  4. DC and D only

Correct answer

B. B and C only

Step-by-step solution

The electronic configuration of Cr is [Ar] 3d^5 4s^1 and Mn is [Ar] 3d^5 4s^2 . For the first ionization enthalpy, the electron is removed from the 4s orbital. Mn has a fully filled 4s^2 configuration and a higher effective nuclear charge compared to Cr. Thus, the first ionization enthalpy of Mn is greater than that of Cr ( _i H₁ : Mn > Cr). This makes statement C correct. After the first ionization, the electronic configurations become: Cr^+ : [Ar] 3d^5 Mn^+ : [Ar] 3d^5 4s^1 For the second ionization enthalpy, the

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