Answer :
Final answer:
The lanthanide series is a group of metallic f-block elements with atomic numbers 58-71. They are located below the main body of the periodic table and have their valence electrons in f orbitals.
Explanation:
The ________ is the lanthanide series, which consists of the metallic f-block elements with atomic numbers 58-71. These elements include cerium (Ce) through lutetium (Lu). They are located below the main body of the periodic table and have their valence electrons in f orbitals. An example of an element in this series is neodymium (Nd), with atomic number 60.