Question

Assertion: Manganese (atomic number $25$) has a less favourable electron affinity than its neighbours on either side because
Reason: The manganese has stable, $[Ar]^{18} 3d^5 4s^2$ electrons configuration

• A. If both A and R are correct and R is the correct explanation of A.
• B. If both A and R are correct but R is not the correct expalnation of A.
• C. A is true but R is false.
• D. A is false but R is true.
• E. A and R both are false.

Answer 1

Answer: (A)

The magnitude of an element’s electron affinity depends on the element’s valence shell electrons configuration.
${ }_{25} Mn =[ Ar ]^{18} 3 d ^{5} 4 s ^{2}$ configuration, ${ }_{24} Cr =[ Ar ]^{18} 3 d ^{5} 4 s ^{1}$ configuration, ${ }_{26} Fe =[ Ar ]^{18} 3 d ^{6} 4 s ^{2}$ configuration