Electron configuration The arrangements of electrons above the last closed shell noble gas. Melting point The temperature at which the solid—liquid phase change occurs. Boiling point The temperature at which the liquid—gas phase change occurs. Sublimation The transition of a substance directly from the solid to the gas phase without passing through a liquid phase. Relative atomic mass The mass of an atom relative to that of carbon This is approximately the sum of the number of protons and neutrons in the nucleus.
Where more than one isotope exists, the value given is the abundance weighted average. Isotopes Atoms of the same element with different numbers of neutrons. CAS number The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems.
Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture. Where the element is most commonly found in nature, and how it is sourced commercially.
Atomic radius, non-bonded Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced. These values were determined using several different methods.
Covalent radius Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination. Electron affinity The energy released when an electron is added to the neutral atom and a negative ion is formed.
Electronegativity Pauling scale The tendency of an atom to attract electrons towards itself, expressed on a relative scale. First ionisation energy The minimum energy required to remove an electron from a neutral atom in its ground state. The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0.
The sum of the oxidation states within a compound or ion must equal the overall charge. Data for this section been provided by the British Geological Survey.
An integrated supply risk index from 1 very low risk to 10 very high risk. This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores. The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply. The availability of suitable substitutes for a given commodity.
The percentage of an element produced in the top producing country. The higher the value, the larger risk there is to supply. The percentage of the world reserves located in the country with the largest reserves. A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators. Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K.
A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.
A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate.
It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site.
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Jump to main content. Periodic Table. Glossary Allotropes Some elements exist in several different structural forms, called allotropes. Glossary Group A vertical column in the periodic table.
Fact box. Glossary Image explanation Murray Robertson is the artist behind the images which make up Visual Elements. Appearance The description of the element in its natural form.
Biological role The role of the element in humans, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. Uses and properties. Image explanation. The image represents the former use of radium in luminous paint used for clock and watch dials. Radium now has few uses, because it is so highly radioactive. Radium is sometimes used to treat prostate cancer that has spread to the bones.
Because bones contain calcium and radium is in the same group as calcium, it can be used to target cancerous bone cells. It gives off alpha particles that can kill the cancerous cells. Radium used to be used in luminous paints, for example in clock and watch dials. Although the alpha rays could not pass through the glass or metal of the watch casing, it is now considered to be too hazardous to be used in this way.
Biological role. Radium has no known biological role. It is toxic due to its radioactivity. Natural abundance. Radium is present in all uranium ores, and could be extracted as a by-product of uranium refining.
Individuals may be exposed to higher levels of radium if they live in an area where there are higher levels of radium in rock and soil.
Radium concentrations in food and air are very low. The concentration of radium in drinking water is generally low, but some regions have higher concentrations due to local geology. The amount of radium allowed in drinking water from community water systems is regulated. Private wells are not regulated. In some geologic formations, oil and gas production can concentrate radium, often in pipe scale. Working in a uranium mine or in a plant that processes ore can lead to higher exposures.
Phosphate rocks typically contain slightly higher levels of both uranium and radium and can raise exposures in phosphate mining areas. Source: Oak Ridge Associated Universities. Historically, radium was used in medical treatments and devices and for passive illumination of aircraft gauges.
Contact your state radiation control program if you find such a device. Chronic exposure to high levels of radium can result in an increased incidence of bone, liver or breast cancer. As radium decays it creates a radioactive gas, radon.
Radon is common in many soils and can collect in homes and other buildings. Radon is the second leading cause of lung cancer in the United States. A article by Ashley Lehman, an American researcher, published in the Journal of Nuclear Medicine , discusses how the medication used in the above study, radium dichloride Xofigo , works. When radium encounters bone, it behaves similarly to calcium and gravitates toward where new bone formation is occurring.
The radium in the medication collects in the bony metastatic sites there the damage from alpha particles being emitted by the decaying radium is primarily limited to the surrounding cancerous tissue as the alpha particles only travel short distances. The study concluded that using radium was a promising treatment for those with prostate cancer and that the same treatment was currently being studied with in breast cancer patients who have developed bone metastases. There are several ongoing trials for using radium for breast cancer, including a double-blind, placebo-controlled trial by a group of American researchers, with an abstract published in the American Association for Cancer Research in The study is aiming to get a total of participants to study the effects and safety of using radium to treat bony metastatic sites caused by breast cancer.
Live Science. Rachel Ross.
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