where are the actinide and lanthanide elements found
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title: Actinide text: the lanthanides, the actinides form a family of elements with similar properties. Within the actinides, there are two overlapping groups: transuranium elements, which follow uranium in the periodic table—and transplutonium elements, which follow plutonium. Compared to the lanthanides, which (except for promethium) are found in nature in appreciable quantities, most actinides are rare. The majority of them do not even occur in nature, and of those that do, only thorium and uranium do so in more than trace quantities. The most abundant or easily synthesized actinides are uranium and thorium, followed by plutonium, americium, actinium, protactinium, neptunium, and curium. The title: Actinide text: of the periodic table, the lanthanides and the actinides are customarily shown as two additional rows below the main body of the table, with placeholders or else a selected single element of each series (either lanthanum or lutetium, and either actinium or lawrencium, respectively) shown in a single cell of the main table, between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods). Like title: Actinide text: quantities in nature and are commonly synthesized via nuclear reactions conducted with nuclear reactors. For example, under irradiation with reactor neutrons, uranium-238 partially converts to plutonium-239: Actinide The actinide or actinoid (IUPAC nomenclature) series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. Strictly speaking, both actinium and lawrencium have been labeled as group 3 elements, but both elements are often included in any general discussion of the chemistry of the actinide elements. Actinium is the more often omitted of the two, because its placement as a group 3 element is somewhat more title: Actinide text: Actinide The actinide or actinoid (IUPAC nomenclature) series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. Strictly speaking, both actinium and lawrencium have been labeled as group 3 elements, but both elements are often included in any general discussion of the chemistry of the actinide elements. Actinium is the more often omitted of the two, because its placement as a group 3 element is somewhat more common in texts and for semantic reasons: since "actinide" means "like actinium", it has been argued that actinium cannot logically be an actinide, even though IUPAC title: Actinium text: Actinium Actinium is a chemical element with symbol Ac and atomic number 89. It was first isolated by French chemist André-Louis Debierne in 1899. Friedrich Oskar Giesel later independently isolated it in 1902 and, unaware that it was already known, gave it the name emanium. Actinium gave the name to the actinide series, a group of 15 similar elements between actinium and lawrencium in the periodic table. It is also sometimes considered the first of the 7th-period transition metals, although lawrencium is less commonly given that position. Together with polonium, radium, and radon, actinium was one of the first non-primordial