# In what period do the elements in the lanthanide series belong?

Lanthanides and actinides are always assigned their own special Periods in the Periodic Table. Many inorganic chemists refer to them as the $\text{f-element metals}$. Because, $\text{scandium,}$ $\text{ytrrium,}$ and $\text{lanthanum}$ have very similar chemistry, their chemistry is often considered under the same umbrella.