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.
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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 Juan and Fausto Elhuyar Origin of the name The name is derived from the Swedish 'tung sten' meaning heavy stone.
Glossary Group A vertical column in the periodic table. As described above, each tungsten atom is composed of 74 protons and 74 electrons in its chemical makeup. The electrons of the atom are found in 6 different layers surrounding the nucleus. The outer layer contains only 2 electrons.
The next layer contains 12 electrons. The following or fourth layer from the nucleus contains a total of 32 electrons. The third shell contains 18 electrons.
The second electron from the nucleus contains 8 shells. The innermost layer contains 2 electrons. Tungsten is a very dense metal, and still among the strongest of all metals, it can also be pretty brittle.
In fact, it is possible to cut a piece of tungsten with something as common as a hacksaw. This is due to the amazing qualities that Tungsten possesses. With the exception of Carbon, Tungsten has the highest melting point of all elements. Melting means when the element begins to turn into liquid. In the universe, neutrons are abundant, making up more than half of all visible matter.
It has no electric charge and a rest mass equal to 1. The neutron has a mean square radius of about 0.
Atomic nuclei consist of protons and neutrons, which attract each other through the nuclear force , while protons repel each other via the electric force due to their positive charge.
These two forces compete, leading to various stability of nuclei. There are only certain combinations of neutrons and protons, which forms stable nuclei. Neutrons stabilize the nucleus , because they attract each other and protons , which helps offset the electrical repulsion between protons. As a result, as the number of protons increases, an increasing ratio of neutrons to protons is needed to form a stable nucleus.
If there are too many or too few neutrons for a given number of protons, the resulting nucleus is not stable and it undergoes radioactive decay. Unstable isotopes decay through various radioactive decay pathways, most commonly alpha decay, beta decay, or electron capture. Many other rare types of decay, such as spontaneous fission or neutron emission are known. It should be noted that all of these decay pathways may be accompanied by the subsequent emission of gamma radiation.
Pure alpha or beta decays are very rare. The periodic table is a tabular display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and chemical properties. The electron configuration is the distribution of electrons of an atom or molecule or other physical structure in atomic or molecular orbitals.
Knowledge of the electron configuration of different atoms is useful in understanding the structure of the periodic table of elements. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms.
Atoms with different numbers of protons must be different elements. All atoms of the same element have the same number of protons — for example, every oxygen atom has eight protons in its nucleus.
For instance if you were asked to find out how many protons, neutrons and electrons a tungsten atom has if its mass number is you can use the periodic table to help you. The atomic number of tungsten is 74, so a tungsten atom has 74 protons. Another example: Phosphorus is in group five of the periodic table. So how would you work out how many electrons a phosphorus atom has in its outermost energy level?
Well, we know that the way the periodic table is organised means that elements in the same group have the same number of electrons in their outermost energy level.
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