High School

A ________ is any one of a series of metallic f-block elements with atomic numbers 58-71.

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.