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AP EAMCET · Chemistry · Structure of Atom

In the electronic configuration of which of the given elements, Aufbau principle or \((n+l)\) rule is violated?

  1. A \(\mathrm{Mn}\)
  2. B Ga
  3. C \(\mathrm{La}\)
  4. D Pu
Verified Solution

Answer & Solution

Correct Answer

(C) \(\mathrm{La}\)

Step-by-step Solution

Detailed explanation

Lanthanum has one electron in \(5 d\)-orbital even through, it is before elements with electrons in \(4 f\)-orbitals. It is because in La, the \(4 f\) and \(5 d\) electrons are so close in energy. Therefore, it violates Aufbau principle.