Question

What are inner transition elements?

Answer 1

1. Inner transition elements are the elements in which the differentiating electrons enter into the (n − 2) f-subshell (the f-orbitals of the antepenultimate shell).
2. They are placed separately at the bottom of the periodic table in the f-block.
3. They consist of two series: lanthanoids (from Ce, Z = 58 to Lu, Z = 71) and actinoids (from Th, Z = 90 to Lr, Z = 103).
4. Also called f-block elements or rare earth elements, they are metals and occur rarely in the Earth’s crust.
5. Lanthanoids fill 4f orbitals and actinoids fill 5f orbitals in their atoms.