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Encyclopedia entry: solar system abundances of the chemical elements
- Article from:
- The Oxford Companion to the Earth
- Author:
Copyright© The Oxford Companion to the Earth 2000, originally published by Oxford University Press 2000. (Hide copyright information)
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solar system abundances of the chemical elements
Relative abundances of the chemical elements in the solar system span some 12 orders of magnitude (Fig. 1). The two lightest elements, hydrogen (H) and helium (He), together constitute more than 99 per cent of the atoms and the mass of the solar system. At the opposite end of the abundance scale are the rarest heavy elements, such as tantalum (Ta), rhenium (Re), thorium (Th), and uranium (U). Even elements as familiar as oxygen (O), iron (Fe), copper (Cu), and silver (Ag) are 10
3
–10
11
times less abundant than hydrogen.
The most accessible solar system materials are the rocks of the Earth's crust and upper mantle. Elemental abundance ...