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NEETChemistryd and f Block Elements

Why do some elements have exceptions to the general electronic configuration due to the energy difference between (n-1)d and ns orbitals?

Options

  1. ABecause (n-1)d orbitals can hold more electrons
  2. BBecause the energy gap between (n-1)d and ns orbitals is small
  3. CBecause (n-1)d orbitals have a higher energy level
  4. DBecause the ns orbitals are completely filled

Correct answer

B. Because the energy gap between (n-1)d and ns orbitals is small

Step-by-step solution

The (n–1) stands for the inner d orbitals which may have one to ten electrons and the outermost ns orbital may have one or two electrons. However, this generalisation has several exceptions because of very little energy difference between (n-1)d and ns orbitals

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