what are inner transition elements mention their position and also mention their reason behind their numbers
Answers
Answer:
The elements constituting the f-block are those in which 4f and 5f orbitals are progressively filled. These elements are formal members of group 3 but are shown separately as f-block of the periodic table. The elements of f-block are also called inner transition elements.
The two series of inner transition elements that are 4f and 5f series are known as lanthanoids and actinoids respectively. The inner transition elements such as U, Th and Pa are providing good sources of nuclear energy.
The electronic configuration of the inner transition elements are 4f1-145d0-16s2 for the lanthanons beginning at cerium and ending at lutetium (Z = 71) and 5f1-146d0-17s2 for the actions beginning with thorium (Z = 90) and ending with lawrencium (Z = 103).
Inner Transition Elements
Because of the similar outer shell configurations, and energies of the f orbital electrons, the lanthanons as well as the actions are expressed to give state III without exceptions. All the elements in a series would have similar properties because of the same size and outer shell configuration, making their separation from one another tedious.
On account of similar outer shell electronic configuration and energies of f-orbital electrons, the lanthanides and actinides are expected to give oxidation state +3 without -exception. All the elements in a series have similar properties due to the same size and similar outer shell electronic configuration making their separation from each other rather difficult.