The actinides are the elements with atomic numbers 89 (actinium) through 103 (Lawrencium). With each unit increase in atomic number, the atom of each succeeding actinium element has one additional 5f electron. Thus, the actinium series of fourteen...

The actinide (or actinoid) series encompasses the 15 chemical elements that lie between actinium and lawrencium on the periodic table, with atomic numbers 89 - 103[1]. The actinide series derives its name from the first element in the series, actinium,...