Catenation is a property of an atom in which it has the tendency to bind with the elements of the same atom, which leads to the formation of a larger or longer chain.
The best example of catenation is a carbon () as it has the tendency to form a maximum of 4 bonds with other elements like carbon(), hydrogen(), etc via a covalent bond.
For example methane (), ethane () are the hydrocarbons formed by the catenation property of the Carbon.