Actinides

The electronic configurations of the actinides utilize the //f// sub level. Depending on your interpretation of the periodicity of the elements, the series begins with actinium, thorium, or even lawrencium. The actinides (An) are prepared by reduction of AnF 3 or AnF 4 with vapors of Li, Mg, Ca, or Ba at 1100 - 1400°C. They are on the lowest row of the periodic table and are very powerful if used right. they are radioactive and have electropositive materials. They are metals and tarnish readily in the air. Actinides Include thorium, protiactimiun, uramium, neptunium, americium, plutonium, curium, californium, fermenium,
 * 89 [|Ac] || 90 [|Th] || 91 [|Pa] || 92 [|U] || 93 [|Np] || 94 [|Pu] || 95 [|Am] || 96 [|Cm] || 97 [|Bk] || 98 [|Cf] || 99 [|Es] || 100 [|Fm] || 101 [|Md] || 102 [|No] || 103 [|Lr] ||
 * Common Properties of the Actinides **

Actinides share the following common properties:
 * All actinides are radioactive.
 * Actinides are highly electropositive.
 * The metals tarnish readily in air.
 * Actinides are very dense metals with distinctive structures. Numerous allotropes may be formed (plutonium has at least 6 allotropes
 * They react with boiling water or dilute acid to release hydrogen gas.
 * Actinides combine directly with most nonmetals.

__** How It Works: **__ The Transition Metals Why are actinides and lanthanides set apart from the periodic table? This can __best__ be explained by reference to the transition metals and their characteristics. Actinides and lanthanides are referred to as inner transition metals, because, although they belong to this larger family, they are usually considered separately—rather like grown children who have married and started families of their own.

Actinide Series is a series of radioactive metallic elements in Group 3 of the periodic table. The 14 embers of the series are called actinides with atomic numbers 90 through 103. Thorium and uranium are the only actinides ound in the earth's crust in appreciable quantities.



More on Actinides and Nuclear Chemistry The group of elements known as the actinides, are the elements from actinium (element 89) to lawrencium (element 103). All members of the series can resemble actinium in their chemical and electronic properties, and so they form a separate group within the periodic table. (An element's atomic number is the sum of the protons and neutrons in the nuclei of its atoms.) All actinides are metals and all are radioactive. As a result, they dominate the study of nuclear chemistry. The elements emit energy in the form of alpha particles, beta particles, or gamma rays. By emitting these particles, the atoms lose protons and therefore become another element with a lower atomic number. If the immediate product of radioactive decay is radioactive, it also decays to form another element. This process continues until a stable element is formed. Actinides undergo radioactive decay at different rates; that is, they have different half-lives. Elements with higher atomic numbers have short half-lives and rapid radioactive decay. Some actinides with lower atomic numbers, however, have half-lives ranging between thousands to millions of years. The two actinides of most interest to Livermore scientists are uranium and Plutonium. Uranium, a silver and lustrous metal, has four main isotopes. Because uranium-235 is fissionable, it is used to fuel nuclear power plants and as a component in nuclear weapons. Plutonium is a silver-gray metal that has 16 isotopes. The isotope of chief interest is plutonium-239, which, like uranium-235, is fissionable. Most nuclear weapons are based on plutonium-239, while plutonium-238 is used as a power source in long-mission space probes