Question

Give a reason for the following: 

Actinoids show irregularities in their electronic configurations.

Answer 1

Actinoids show irregularities in their electronic configurations because the energy differences between 5f, 6d and 7s subshells are very small; hence, an electron can be occupied in any of the subshells. They have the electronic configuration of 7s² with variation of occupancy in 5f and 6d orbitals.

Answer 2

Actinoids show irregularities in their electronic configuration are related to their stabilities of the f₀,f₇, and f₁₄ occupancies of the 5f orbital.