Question

What are lanthanides?

Answer 1

These are the inner transition elements or f-block elements:
The lanthanoids are present in the 6th period of the periodic table. The lanthanide series consists of a total of 14 elements from (Cerium) ${}_{58}Ce$ to (Leuterium) ${}_{71}Lu$. They are also called as lanthanoids or rare earth elements as they occur scarcely in the earth's crust.
In general, their outermost
Electronic configuration is 4f 1 - 14 6s 2.
Due to lanthanoid contraction, there is a gradual decrease in atomic and ionic radii with an increase in atomic number. The lanthanoids exhibit mainly +3 oxidation state. However, sometimes +2 and +4 oxidation states are also exhibited.