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!
Ultrapure silicon doped with boron or phosphorus is used as semiconductors in transistors, which are heavily employed in computers, solar panels, and other applications. Silica which is primarily silicon dioxide, SiO 2 , is used in the manufacture of glass.
Silicones, which consist of chains of alternating silicon and oxygen atoms, are used in oils, lubricants, and silicone rubber. Germanium is a hard, grayish white element with a metallic luster. The name of the element is derived from the Latin word for Germany, Germania. It is found in the Earth's crust at a concentration of 2 ppm, making it the 52nd most abundant element.
It is found in the ores argyrodite [Ag 8 GeS 6 ] and germanite [Cu 13 Fe 2 Ge 2 S 16 ], but is more frequently obtained as a by-product of the refining of zinc. Like silicon, germanium is used as a semiconductor, and is widely used in the computer industry. Silicon and germanium are both metalloids , having some characteristics of both metals and nonmetals. The existence of germanium was predicted by Dimitri Mendeleev in from a blank space in his periodic table beneath silicon; before it was actually found, the hypothetical element was referred to as "eka-silicon.
Tin is a soft, silvery-white metal. The name of the element is derived from the Anglo-Saxon word for the metal, while the chemical symbol "Sn" is derived from the Latin name for the metal, stannum. It is found in the Earth's crust at a concentration of 2 ppm, making it the 49th most abundant element.
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. Discovery date Discovered by Martin Heinrich Klaproth Origin of the name The name is derived from the Arabic, 'zargun', meaning gold coloured. 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 Ancient Egyptians used zircon gemstones in jewellery.
For the Ancient Egyptians the scarab beetle represented here was a symbol of regeneration and creation, conveying ideas of transformation, renewal and resurrection. A hard, silvery metal that is very resistant to corrosion. Zirconium does not absorb neutrons, making it an ideal material for use in nuclear power stations.
Nuclear reactors can have more than , metres of zirconium alloy tubing. With niobium, zirconium is superconductive at low temperatures and is used to make superconducting magnets. Zirconium metal is protected by a thin oxide layer making it exceptionally resistant to corrosion by acids, alkalis and seawater.
For this reason it is extensively used by the chemical industry. Zirconium IV oxide is used in ultra-strong ceramics. It is used to make crucibles that will withstand heat-shock, furnace linings, foundry bricks, abrasives and by the glass and ceramics industries. It is so strong that even scissors and knives can be made from it. It is also used in cosmetics, antiperspirants, food packaging and to make microwave filters. Zircon is a natural semi-precious gemstone found in a variety of colours.
The most desirable have a golden hue. The element was first discovered in this form, resulting in its name. Cubic zirconia zirconium oxide is a synthetic gemstone. The colourless stones, when cut, resemble diamonds. Biological role. Zirconium has no known biological role. It has low toxicity. Natural abundance. Zirconium occurs in about 30 mineral species, the major ones being zircon and baddeleyite.
More than 1. Most baddeleyite is mined in Brazil. Zirconium metal is produced commercially by first converting zircon to zirconium chloride, and then reducing the chloride with magnesium. Help text not available for this section currently. Elements and Periodic Table History. Gems that contain zirconium were known in ancient times as zircon.
Klaproth failed to isolate the pure metal itself, and Humphry Davy also failed when he tried electrolysis in Totally pure zirconium was only produced in by the Dutch chemists Anton Eduard van Arkel and Jan Hendrik de Boer by the decomposition of zirconium tetraiodide ZrI 4. These days the metal is produced in bulk by heating zirconium tetrachloride ZrCl 4 with magnesium.
Atomic data. Glossary Common oxidation states The oxidation state of an atom is a measure of the degree of oxidation of an atom. Oxidation states and isotopes. Glossary Data for this section been provided by the British Geological Survey. Relative supply risk An integrated supply risk index from 1 very low risk to 10 very high risk.
Recycling rate The percentage of a commodity which is recycled. Substitutability The availability of suitable substitutes for a given commodity. Reserve distribution The percentage of the world reserves located in the country with the largest reserves. Political stability of top producer A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators.
Political stability of top reserve holder A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators. Supply risk. Relative supply risk 5. Young's modulus A measure of the stiffness of a substance. Shear modulus A measure of how difficult it is to deform a material. Bulk modulus A measure of how difficult it is to compress a substance. Vapour pressure A measure of the propensity of a substance to evaporate.
Pressure and temperature data — advanced. How much energy does it take to go from alpha to beta? Enthalpy Question. Which reference electrode to select for electrochemical measurements? The one with Vycor or ceramic frit? Can someone please explain and show me how to di this question please Zr has atomic number 40 , so Zr has atomic number 40 , so it need to lose 4 electrons to gain noble gas configuration of the noble gas Kr.
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