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. Copyright of and ownership in the Images reside with Murray Robertson. The RSC has been granted the sole and exclusive right and licence to produce, publish and further license the Images. The RSC maintains this Site for your information, education, communication, and personal entertainment.
You may browse, download or print out one copy of the material displayed on the Site for your personal, non-commercial, non-public use, but you must retain all copyright and other proprietary notices contained on the materials. You may not further copy, alter, distribute or otherwise use any of the materials from this Site without the advance, written consent of the RSC. The images may not be posted on any website, shared in any disc library, image storage mechanism, network system or similar arrangement.
Pornographic, defamatory, libellous, scandalous, fraudulent, immoral, infringing or otherwise unlawful use of the Images is, of course, prohibited. If you wish to use the Images in a manner not permitted by these terms and conditions please contact the Publishing Services Department by email. If you are in any doubt, please ask. Commercial use of the Images will be charged at a rate based on the particular use, prices on application. In such cases we would ask you to sign a Visual Elements licence agreement, tailored to the specific use you propose.
The RSC makes no representations whatsoever about the suitability of the information contained in the documents and related graphics published on this Site for any purpose. All such documents and related graphics are provided "as is" without any representation or endorsement made and warranty of any kind, whether expressed or implied, including but not limited to the implied warranties of fitness for a particular purpose, non-infringement, compatibility, security and accuracy.
In no event shall the RSC be liable for any damages including, without limitation, indirect or consequential damages, or any damages whatsoever arising from use or loss of use, data or profits, whether in action of contract, negligence or other tortious action, arising out of or in connection with the use of the material available from this Site.
Nor shall the RSC be in any event liable for any damage to your computer equipment or software which may occur on account of your access to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused by a virus, bug or otherwise.
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.
Group 14 Melting point 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. Germanium was used in early transistors similar to the one featured here. Germanium is a semiconductor. The pure element was commonly doped with arsenic, gallium or other elements and used as a transistor in thousands of electronic applications.
Today, however, other semiconductors have replaced it. Germanium oxide has a high index of refraction and dispersion. This makes it suitable for use in wide-angle camera lenses and objective lenses for microscopes. This is now the major use for this element. Both germanium and germanium oxide are transparent to infrared radiation and so are used in infrared spectroscopes.
Biological role. Germanium has no known biological role. The element is non-toxic. The burning of carbon and petroleum products fossil fuels provides most of the energy which we consume, and contributes to global warming through the release of carbon dioxide into the atmosphere. Carbon is used is the refining of iron and other metals the oxygen in the ores is carried away in the form of carbon dioxide, leaving behind the elemental metal.
Small amounts of carbon are added to iron to make an alloy called steel, which is harder than pure iron. Activated charcoal is a finely powdered form of carbon used to filter out impurities from water or gases.
Carbon is taken up by green plants in the form of carbon dioxide, CO 2 ; in the process of photosynthesis, the carbon in the carbon dioxide is transformed into carbohydrates sugars , lipids, proteins, and all of the other organic molecules which are essential to life.
Most carbon is in the form of the carbon isotope Carbon, which is also non-radioactive, accounts for 1. Carbon is particularly important in nuclear magnetic resonance spectroscopy see the section on Hydrogen ; organic molecules contain small amounts of carbon, which responds to magnetic fields in a similar fashion as hydrogen Carbon, which consists of 6 protons and 8 neutrons, is an unstable isotope produced the reaction of free neutrons produced from cosmic rays with nitrogen in the upper atmosphere.
Carbon undergoes beta decay to produce nitrogen, with a half-life of years:. The amount of carbon thus produced is extremely small — approximately 7 kilograms per year — but small amounts of this carbon are taken up in the form of carbon dioxide along with the "normal" isotopes of carbon by green plants, and this isotope also becomes incorporated into the things that eat the green plants and also the things that eat the things that eat the green plants — and so on.
Once an organism dies, it stops taking in carbon or anything else, for that matter , and the carbon that it had at the moment of death decays, and is no longer replaced. By measuring the amount of carbon remaining in an organic sample, it is possible to determine how long ago the organism died. This technique works for carbon-containing materials that are up to about 50, years old; beyond that, there is too little carbon remaining to get an accurate date, and some other form of radiometric dating must be used.
This technique was developed by Willard F. Libby in the s, who received the Nobel Prize in Chemistry in for this work. Silicon is a dark gray element with a metallic luster. The name of the element is derived from the Latin word for flint, silicis. In the form of silica SiO 2 or one of the silicates SiO 4 4- , it is found in many different minerals, including clay, quartz, zircon, feldspar, mica, zeolites, aluminosilicates, sand, etc. It is also found in the gemstones opal, agate, rhinestone, and amethyst.
Silicon is one of the most important elements on the periodic table at least from the perspective of computers! High purity germanium single crystal detectors can precisely identify radiation sources e. Germanium is less abundant than either tin or lead , which are the heavier component metals of group 14, and it is less easily accessed because geological processes have contracted only small amounts of it into minerals, so that it tends to be widely dispersed.
Germanium ores are rare. Germanium is widely distributed in ores of other metals, such as zinc, and that which is required for manufacturing purposes is recovered as a by-product from the flue-dusts of zinc smelters. World production is about 80 tonnes per year.
Health effects of Germanium The estimated daily intake is around 1 mg, and there have been claims that germanium could be beneficial to health, athough this has never been proved scientifically. A high intake of germanium was supposed to improve the immune system, bost the body's oxygen supply, make a person feel more alive and destroy damaging free radicals. In addition was said to protect the user against radiation. In in the UK the Governement's Department of Health warned against germanium supplements, noting that they had no nutritional or medical value and that taking them consituted a risk to health, rather than a benefit.
Germanium hydride and germanium tetrahydride are extremely flammable and even explosive when mixed with air. The accuracy of Mendeleev's prediction increased chemists' confidence in the periodic table. There have been claims that germanium may be beneficial for health, including improving the immune system, oxygen supply in the body, and destroying free radicals. There is, however, little to no scientific support of these claims, and using germanium supplements or medications can lead to many side effects, including kidney damage, anemia, muscle weakness and lack of coordination, and elevated liver enzymes, according to Healthline.
In experiments, a derivative of germanium called spirogermanium has been shown to inhibit replication in certain cancer cells, but human studies show it has adverse effects and is not suitable as an anticancer treatment, according to the Memorial Sloan Kettering Cancer Center.
Germanium is commonly used in detectors in a variety of fields, according to a study published in Applied Physics Letters in
0コメント