Why are f-block elements called "Inner-transition elements" ?
The f- block elements are known as inner transition elements because they involve the filling of inner sub-shells (4f or 5f). Their electronic configuration has a f-orbital (or they have valence electrons f-orbitals). These include Lanthanide and Actinide series in the periodic table.
1. Lanthanides: It consists of elements that follow lanthanum and involve the filling of 4f subshell.
2. Actinides: It consists of elements that follow Actinium and involve the filling of 5f subshell.
since d block elements are placed in middle of s and p and their properties are also betwwen the properties of s and p so the are called as transition elements . and f block is placed betwwen the d block so it is called inner transition element. transition itself means something that is place betwwen the two..........