Question

Write and explain the general electronic configuration of lanthanoids and actinoids 2

Answer 1

hey friend here is your answer^^

Lanthanoids: has electronic configuration [Xe] 4f1–14 5d0–16s2. It is energetically favourable to move single 5d electron to 4f level in most of lanthanoids series except Ce,Gd and Lu. Gd has 5d1 arrangement bcz it leads to stable half filled configuration and in case of Lu to stable filled f-shell configuration.

Actinoids: There are 14 elements,after actinium (Ac), in which 5f orbitals are successively filled, starting Th(90) to Lr(103). Ac , the d-block element preceding 5f series has outer shell structure 6d17s2. For the first 4 actinoids Th,Pa,U and Np, the difference between the energy level of 5f and 6d orbital is small. Thus in these element electrons may occupy either 5d or 6f orbitals . From Pu onwards, the energy of 5f orbital becomes lower and electrons fill the orbitals as in case of lanthanoids.