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. Discovery date Discovered by Daniel Rutherford Origin of the name The name is derived from the Greek 'nitron' and 'genes' meaning nitre forming.
Allotropes N 2. 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 wheat sheaf symbol and lightning reflect the importance of nitrogen to living things. Nitrogen is important to the chemical industry.
It is used to make fertilisers, nitric acid, nylon, dyes and explosives. To make these products, nitrogen must first be reacted with hydrogen to produce ammonia.
This is done by the Haber process. Nitrogen gas is also used to provide an unreactive atmosphere. It is used in this way to preserve foods, and in the electronics industry during the production of transistors and diodes. Large quantities of nitrogen are used in annealing stainless steel and other steel mill products.
Annealing is a heat treatment that makes steel easier to work. Liquid nitrogen is often used as a refrigerant. It is used for storing sperm, eggs and other cells for medical research and reproductive technology.
It is also used to rapidly freeze foods, helping them to maintain moisture, colour, flavour and texture. Biological role. It is taken up by green plants and algae as nitrates, and used to build up the bases needed to construct DNA, RNA and all amino acids. Amino acids are the building blocks of proteins. Animals obtain their nitrogen by consuming other living things.
They digest the proteins and DNA into their constituent bases and amino acids, reforming them for their own use. Microbes in the soil convert the nitrogen compounds back to nitrates for the plants to re-use.
Crop yields can be greatly increased by adding chemical fertilisers to the soil, manufactured from ammonia. If used carelessly the fertiliser can leach out of the soil into rivers and lakes, causing algae to grow rapidly. Large amounts of nitrogen are combined with hydrogen to produce ammonia in a method known as the Haber process. Large amounts of ammonia are then used to create fertilizers, explosives and, through a process known as the Ostwald process, nitric acid HNO 3.
Nitrogen gas is largely inert and is used as a protective shield in the semiconductor industry and during certain types of welding and soldering operations. Oil companies use high pressure nitrogen to help force crude oil to the surface.
Liquid nitrogen is an inexpensive cryogenic liquid used for refrigeration, preservation of biological samples and for low temperature scientific experimentation. Jefferson Lab's Frostbite Theater features videos of many basic liquid nitrogen experiments, such as this one:. The atmosphere of Mars, by comparison, is only 2. From an exhaustible source in our atmosphere, nitrogen gas can be obtained by liquefaction and fractional distillation.
Nitrogen is found in all living systems as part of the makeup of biological compounds. The French chemist Antoine Laurent Lavoisier mistakenly named nitrogen azote , meaning without life. However, nitrogen compounds are found in foods, organic materials, fertilizers, poisons, and explosives. Nitrogen, as a gas is colorless, odorless, and generally considered an inert element. Nitrogen gas can be prepared by heating a water solution of ammonium nitrite NH 4 NO 3.
Sodium nitrate NaNO 3 and potassium nitrate KNO 3 are formed by the decomposition of organic matter with compounds of these metals present. In certain dry areas of the world these saltpeters are found in quantity and are used as fertilizers.
The nitrogen cycle is one of the most important processes in nature for living organisms. In other words, Nature has provided a method to produce nitrogen for plants to grow.
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