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. Image showing periodicity of the chemical elements for atomic radius (empirical) in a 3D periodic table column style.A vertical column in the periodic table.

Image showing periodicity of the chemical elements for atomic radius (empirical) in a 3D spiral periodic table column style. Image showing periodicity of the chemical elements for atomic radius (empirical) in a spiral periodic table heatscape style. Image showing periodicity of the chemical elements for atomic radius (empirical) in a periodic table heatscape style. Image showing periodicity of the chemical elements for atomic radius (empirical) in a periodic table cityscape style. Values are given to an accuracy of about 5 pm. A single set of radii is very useful for most purposes, however, for very accurate work adjustments would have to be made to the values quoted to reflect the specific environment of the element (such as coordination number). The idea is that for a bond A-B, the atomic radius of A added to the atomic radius of B will give a reasonable estimate for the A-B separation in whatever environment. Slater are an empirical set of atomic radii derived by the careful comparison of bond lengths in over 1200 bond types in ionic, metallic, and covalent crystals and molecules (reference 1).

Atomic radius of element