Location of actinides on the periodic table
The actinide series is the 15 chemical elements between actinium and lawrencium on the periodic table. They have the atomic numbers between 89 and 103. The actinide series is named after actinium. All of the elements are radioactive. Uranium is the most common natural actinide, and thorium second.
The term ‘actinide series’ has been derived from the first element of the series, actinium. The symbol An is used while referring to any of the actinide series elements.