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Allotropes Some elements exist in several different structural forms, called allotropes. Each allotrope has different physical properties. For more information on the Сексмир ru Elements image see the Uses and properties section below.
Group A vertical column in the periodic table. Members of a group typically have similar properties and electron configurations in their outer shell. Period A horizontal row in the periodic table. The atomic number of each element increases by one, reading from left to right. Block Elements are organised into blocks by the orbital type in which the outer electrons are found. These blocks are named for the characteristic spectra they produce: Atomic number The number of protons in an atom.
Electron configuration The arrangements of electrons above сексмир ru 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 сексмир ru 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 сексмир ru 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 сексмир ru of neutrons. CAS number The Chemical Abstracts Service registry number сексмир ru 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 сексмир ru where the сексмир ru explains сексмир ru 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, сексмир ru on a relative scale. First ionisation energy The minimum energy required to remove an electron from a neutral atom in its ground state. Сексмир ru 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 сексмир ru supply. The availability of suitable substitutes for a given сексмир ru. The сексмир ru of an element produced in the top сексмир ru 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 сексмир ru largest reserves, сексмир ru from World Bank governance indicators.
Specific heat capacity is сексмир ru amount of energy needed to change the temperature of a kilogram of a substance by 1 K.
A measure of the сексмир ru of a substance. It provides a measure of how difficult it is to extend a material, with a value сексмир ru 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 сексмир ru to сексмир ru 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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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 сексмир ru 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 сексмир ru to or use of the Site, or your downloading of materials, data, text, software, or images from the Site, whether caused сексмир ru a virus, bug or otherwise. Jump to main content. Glossary Allotropes Some elements exist in several different structural forms, called allotropes.
Glossary Group A vertical column in the periodic table.
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 сексмир ru, animals and plants. Natural abundance Where the element is most commonly found in nature, and how it is sourced commercially. The stylised Cyrillic text is based on a Soviet Russian flag from around Many new uses are emerging for ruthenium.
Most is сексмир ru in the electronics industry for chip resistors and electrical contacts. Ruthenium oxide is used in the chemical industry сексмир ru coat the anodes of electrochemical cells for chlorine production.
Ruthenium is also used in catalysts for ammonia and сексмир ru acid production. Ruthenium compounds can be used in solar cells, which turn light energy into electrical energy. Ruthenium is one of the most effective hardeners for platinum and palladium, and is alloyed with these сексмир ru to make electrical contacts for severe wear resistance.
It is used in some jewellery as an alloy with platinum. Ruthenium сексмир ru no known biological role.
Ruthenium IV oxide сексмир ru highly toxic. Ruthenium is one of the rarest metals on Earth. It is found uncombined in nature; however, it is more commonly found associated with other platinum metals in сексмир ru minerals pentlandite and pyroxinite.
It is obtained commercially from the wastes of nickel refining. Help text not available for this section currently.
Elements and Periodic Table History. The Polish chemist Jedrzej Sniadecki was investigating platinum ores from South America and, in Maywhen he discovered a new metal which he called it vestium.
However, when French chemists tried to сексмир ru his work they were unable to find it in the platinum ore they had. When Sniadecki learned of this he believed he had been сексмир ru and withdrew his claim. Then, inGottfried Osann of the University of Dorpat now Tartu on the Baltic, сексмир ru some platinum from the Ural mountains, and reported finding three new elements which he named pluranium, polinium, and ruthenium. While the first two of these were never to be verified, the third was genuine and in Karl Karlovich Klaus at the University of Kazan extracted, purified, and confirmed it was a сексмир ru metal.
Glossary Common oxidation states The oxidation state of an atom is a measure of сексмир ru degree of oxidation of an atom. Oxidation states and isotopes. Glossary Data for this section been provided сексмир ru the British Geological Survey.