Actinides
The actinide series (or actinoid series) of elements are the 15 metallic chemical elements with atomic numbers from 89 (actinium) to 103 (lawrencium). The actinide elements are all radioactive and can be divided into three series—the thorium series with atomic numbers 90–103, the plutonium series with atomic numbers 94–103, and the uranium series with atomic numbers 90–92.
The actinide elements are relatively poorly understood, as the majority of chemistry has been conducted on the earlier transactinide elements (patented unusual nuclides). With the exception of actinium, Nobelium, and lawrencium, actinides typically display multiple oxidation states and form complex compounds, which makes these elements highly reactive.
Actinides form the second largest group of elements in the periodic table. They are characterized by having valence electrons in the 6s and 5f orbitals, which gives them different characteristics than the other groups. These include a large atomic radius, the ability to form coordinate covalent bonds, a low first ionization energy and a high electron affinity, and the ability to form multiple oxidation states.
The majority of naturally occurring actinides occur in uranium ore, which is abundant in nature. Naturally occurring actinides are produced in the form of the isotope uranium-238. Uranium-238 is an alpha emitter, meaning it emits particles during radioactive decay, and has a half-life of 4.5 billion years.
Actinides are used in many applications, including nuclear power generation and as a source of energy. Nuclear power plants use uranium as a fuel, which is divided into small pieces and placed in the reactor core. Uranium-238 and uranium-235 are two common forms used. The presence of the actinides allows the reactor to generate a significant amount of electricity.
Actinides are also used in the medical field, specifically in radiation therapy. Radionuclides are used to selectively target malignant cells in tumors without damaging healthy cells.
Finally, actinides can be used in the field of research and development. They can be used to study the behavior of molecules and atoms, which can help scientists to create new materials and technologies.
In conclusion, the actinides are an important part of the periodic table, offering a range of uses in many different fields. Though the majority of actinides occur naturally, some can be synthesized to suit specific needs. The unique characteristics of this family of elements give them a wide range of potential applications and make them a valuable resource.
