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The main elements that comprise the human body (including water) can be summarized as CHNOPS. Element Symbol percent mass percent atoms Oxygen O 65.0 24.0 Carbon C 18.5 12.0 Hydrogen H 9.5 62.0 Nitrogen N 2.6 1.1 Calcium Ca 1.3 0.22 Phosphorus P 0.6 0.22 Sulfur S 0.3 0.038 Potassium K 0.2 0.03 Sodium Na 0.2 0.037 Chlorine Cl 0.2 0.024 Magnesium Mg
English: The main elements that compose the human body, by mass percent, are shown from most abundant to least abundant element. The atomic fractions (fractions of atoms) are different due to differing atomic weights. As in water, oxygen contributes the most mass, but hydrogen is the most common atom.
For example, a transfer of a single electron between atoms is a useful approximation for bonds that form between atoms with one-electron more than a filled shell, and others that are one-electron short of a full shell, such as occurs in the compound sodium chloride and other chemical ionic salts. Many elements display multiple valences, or ...
The human body is composed of approximately: 64% water, 20% protein, 10% fat, 1% carbohydrate, 5% minerals. [1] The decomposition of soft tissue is characterized by the breakdown of these macromolecules, and thus a large proportion of the decomposition products should reflect the amount of protein and fat content initially present in the body. [4]
Theories of chemical structure were first developed by August Kekulé, Archibald Scott Couper, and Aleksandr Butlerov, among others, from about 1858. [4] These theories were first to state that chemical compounds are not a random cluster of atoms and functional groups, but rather had a definite order defined by the valency of the atoms composing the molecule, giving the molecules a three ...
John Dalton represented compounds as aggregations of circular atoms, and although Johann Josef Loschmidt did not create physical models, his diagrams based on circles are two-dimensional analogues of later models. [2] August Wilhelm von Hofmann is credited with the first physical molecular model around 1860. [3]
Cations and anions are also typically discrete and can be depicted unambiguously. For simple structures, say <10 atoms, it is helpful to depict all atoms explicitly. For more complex molecules, most hydrogen atoms attached to carbon are omitted, and carbon atoms are represented by vertices. For ease of readability, sans-serif fonts are ...
English: Diagram of an idealized Lithium atom, primarily useful to illustrate the nucleus of an atom. This sort of design is scientifically inaccurate in many important respects, but serves as a powerful mandala of the nuclear age.