These are two groups of what are called "inner transition elements" because the differentiating electron that is in one of the group but not in the one with the next lower atomic number goes into an...
actinides: any of a series of radioactive elements with atomic numbers 89 through 103...
Lanthanide/lanthanoid ) series comprises the 15 elements with atomic numbers 57 through 71.....
They're all...
Calcium is an alkaline earth metal and located in the 4th Period of the periodic table. Lanthanoids only occur in the 6th Period and Actinoids in the 7th Period.