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Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of atomic number; [5] siderophiles shown in yellow. Graphs of abundance against atomic number can reveal patterns relating abundance to stellar nucleosynthesis and geochemistry. The alternation of abundance between even and odd atomic number is ...
Clarke number. Clarke number or clarke is the relative abundance of a chemical element, typically in Earth's crust. The technical definition of "Earth's crust" varies among authors, and the actual numbers also vary significantly.
The abundance of the chemical elements is a measure of the occurrences of the chemical elements relative to all other elements in a given environment. Abundance is measured in one of three ways: by mass fraction (in commercial contexts often called weight fraction), by mole fraction (fraction of atoms by numerical count, or sometimes fraction of molecules in gases), or by volume fraction.
Oxygen is the most abundant element in Earth's crust, and the third-most abundant element in the universe after hydrogen and helium. 2. Dioxygen gas currently constitutes 20.95% molar fraction of the Earth's atmosphere, though this has changed considerably over long periods of time in Earth's history.
The Goldschmidt classification, [1] [2] developed by Victor Goldschmidt (1888–1947), is a geochemical classification which groups the chemical elements within the Earth according to their preferred host phases into lithophile (rock-loving), siderophile (iron-loving), chalcophile (sulfide ore-loving or chalcogen-loving), and atmophile (gas-loving) or volatile (the element, or a compound in ...
The established abundances of chemical elements in urban soils can be considered a geochemical (ecological and geochemical) characteristic, the accumulated impact of technogenic and natural processes at the beginning of the 21st century. The figures estimate average concentrations of chemical elements in the soils of more than 300 cities and ...
Although oxygen is the most abundant element in Earth's crust, due to its high reactivity it mostly exists in compound (oxide) forms such as water, carbon dioxide, iron oxides and silicates. Before photosynthesis evolved, Earth's atmosphere had no free diatomic elemental oxygen (O 2). [2] Small quantities of oxygen were released by geological ...
Abundance (atom fraction) of the chemical elements in Earth's upper continental crust as a function of the atomic number. The rarest elements in the crust (shown in yellow) are not the heaviest, but are rather the siderophile (iron-loving) elements in the Goldschmidt classification of elements. These have been depleted by being relocated deeper ...