Final answer:
There are two series of inner transition elements, the lanthanide series and the actinide series
Step-by-step explanation:
The inner transition elements are metallic elements in which the last electron added occupies an f orbital. There are two series of inner transition elements, namely the lanthanide series and the actinide series. The lanthanide series consists of the elements from lanthanum (La) through lutetium (Lu), while the actinide series consists of the elements from actinium (Ac) through lawrencium (Lr).