Concept
Radium
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Beta particle
A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay. There are two forms of beta decay, β− decay and β+ decay, which produce electrons and positrons respectively. Beta particles with an energy of 0.5 MeV have a range of about one metre in the air; the distance is dependent on the particle energy.
Radiation therapy
Radiation therapy or radiotherapy, often abbreviated RT, RTx, or XRT, is a therapy using ionizing radiation, generally provided as part of cancer treatment to control or kill malignant cells and normally delivered by a linear accelerator. Radiation therapy may be curative in a number of types of cancer if they are localized to one area of the body. It may also be used as part of adjuvant therapy, to prevent tumor recurrence after surgery to remove a primary malignant tumor (for example, early stages of breast cancer).
Astatine
Astatine is a chemical element with the symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth's crust, occurring only as the decay product of various heavier elements. All of astatine's isotopes are short-lived; the most stable is astatine-210, with a half-life of 8.1 hours. A sample of the pure element has never been assembled, because any macroscopic specimen would be immediately vaporized by the heat of its radioactivity. The bulk properties of astatine are not known with certainty.
Francium
Francium is a chemical element with the symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain in which it appears), has a half-life of only 22 minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). Francium's isotopes decay quickly into astatine, radium, and radon.
Relativistic quantum chemistry
Relativistic quantum chemistry combines relativistic mechanics with quantum chemistry to calculate elemental properties and structure, especially for the heavier elements of the periodic table. A prominent example is an explanation for the color of gold: due to relativistic effects, it is not silvery like most other metals. The term relativistic effects was developed in light of the history of quantum mechanics. Initially, quantum mechanics was developed without considering the theory of relativity.
Flame test
A flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic flame emission spectrum (which may be affected by the presence of chloride ion). The color of flames in general also depends on temperature and oxygen fed; see flame color. The test involves introducing a sample of the element or compound to a hot, non-luminous flame, and observing the color of the flame that results.
Jáchymov
Jáchymov (ˈjaːxɪmof; Sankt Joachimsthal or Joachimsthal) is a spa town in Karlovy Vary District in the Karlovy Vary Region of the Czech Republic. It has about 2,400 inhabitants. Jáchymov has a long mining tradition, thanks to which it used to be the second most populous town in the Kingdom of Bohemia in 1534. At first silver was mined here. The silver Joachimsthaler coins minted here since the 16th century gave their name to the Thaler and the dollar.
Radioactive quackery
Radioactive quackery is quackery that improperly promotes radioactivity as a therapy for illnesses. Unlike radiotherapy, which is the scientifically sound use of radiation for the destruction of cells (usually cancer cells), quackery pseudo-scientifically promotes involving radioactive substances as a method of healing for cells and tissues. It was most popular during the early 20th century, after the discovery in 1896 of radioactive decay. The practice has widely declined, but is still actively practiced by some.
Trace radioisotope
A trace radioisotope is a radioisotope that occurs naturally in trace amounts (i.e. extremely small). Generally speaking, trace radioisotopes have half-lives that are short in comparison with the age of the Earth, since primordial nuclides tend to occur in larger than trace amounts. Trace radioisotopes are therefore present only because they are continually produced on Earth by natural processes.
Coprecipitation
In chemistry, coprecipitation (CPT) or co-precipitation is the carrying down by a precipitate of substances normally soluble under the conditions employed. Analogously, in medicine, coprecipitation is specifically the precipitation of an unbound "antigen along with an antigen-antibody complex". Coprecipitation is an important topic in chemical analysis, where it can be undesirable, but can also be usefully exploited.