Introduction to the f-block elements
CHXII08:THE D- & F-BLOCK ELEMENTS

321582 The inner transition elements are the elements in which the added electrons go to

1 (n-1)d-orbitals
2 \({\rm{(n - 2)}}\)f-orbitals
3 (n-1)d-orbitals and (n-2)f-orbitals
4 (n-1)d-orbitals and ns orbitals