![]() The percentage of the world reserves located in the country with the largest reserves. The higher the value, the larger risk there is to supply. The percentage of an element produced in the top producing country. Low = substitution is possible with little or no economic and/or performance impact Medium = substitution is possible but there may be an economic and/or performance impact High = substitution not possible or very difficult. The availability of suitable substitutes for a given commodity. A higher recycling rate may reduce risk to supply. The percentage of a commodity which is recycled. The number of atoms of the element per 1 million atoms of the Earth’s crust. This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores. 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.ĭata for this section been provided by the British Geological Survey.Īn integrated supply risk index from 1 (very low risk) to 10 (very high risk). ![]() ![]() Where more than one isotope exists, the value given is the abundance weighted average.Ītoms of the same element with different numbers of neutrons. This is approximately the sum of the number of protons and neutrons in the nucleus. The mass of an atom relative to that of carbon-12. The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.ĭensity is the mass of a substance that would fill 1 cm 3 at room temperature. The temperature at which the liquid–gas phase change occurs. The temperature at which the solid–liquid phase change occurs. The arrangements of electrons above the last (closed shell) noble gas. These blocks are named for the characteristic spectra they produce: sharp (s), principal (p), diffuse (d), and fundamental (f). The atomic number of each element increases by one, reading from left to right.Įlements are organised into blocks by the orbital type in which the outer electrons are found. Members of a group typically have similar properties and electron configurations in their outer shell.Ī horizontal row in the periodic table. Cesium is second from the bottom of this group, with 6 electron shells, so it fits all the characteristics of a reactive atom, therefore making it the most reactive element.A vertical column in the periodic table. Therefore, the farther you go from those elements, the reactivity of the elements increase.Īlkali metals (situated far away from transitional metals and noble gases) are the most reactive elemental group. Therefore, they can easily travel to other chemically attractive atoms (chemically attractive meaning that their outer electron shells are incomplete and only need one or two more or less electrons to be complete.)Īs you may know, the further down you go ( along the y axis), the more electron shells the elements have and apart from the noble gases, the transitional metals are the least reactive group on the periodic table (due to having moderately balanced outer shells) which are situated towards the centre of the table. The more electron shells, the less magnetic attraction to the nucleus the electrons on the outer shells have. An element's reactivity is based on how many electron shells it has.
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