How many elements are in the lanthanide series?

The lanthanide series contains 15 elements, usually listed from lanthanum (57) to lutetium (71). They are often displayed as a separate row below the main periodic table to keep the chart compact. These elements are sometimes called the rare earths, although several are not especially rare in Earth’s crust. Lanthanides are important in magnets, lasers, glass coloring, and electronic devices. Their chemistry is similar because they fill the 4f electron subshell, which gives them closely related properties.