What are the two series of inner transition metals, and what is the range of elements in the 4f series?

The two series of inner transition metals are the 4f series (lanthanoids) and the 5f series (actinoids). The 4f series comprises elements from Cerium (Ce) to Lutetium (Lu). These elements are commonly known as lanthanides and possess partially filled 4f orbitals. The lanthanides share similar chemical properties and are often collectively studied due to their proximity in the periodic table. They are characterized by the filling of the 4f subshell as their atomic numbers progress, resulting in the expansion of the atomic size and magnetic properties. The 4f series concludes with Lutetium (Lu) in the periodic table.