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  2. Composition of the human body - Wikipedia

    en.wikipedia.org/wiki/Composition_of_the_human_body

    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

  3. CHNOPS - Wikipedia

    en.wikipedia.org/wiki/CHNOPS

    Graphic representation of carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur CHNOPS and CHON are mnemonic acronyms for the most common elements in living organisms. "CHON" stands for c arbon , h ydrogen , o xygen , and n itrogen , which together make up more than 95 percent of the mass of biological systems. [ 1 ] "

  4. Biological roles of the elements - Wikipedia

    en.wikipedia.org/wiki/Biological_roles_of_the...

    A large fraction of the chemical elements that occur naturally on the Earth's surface are essential to the structure and metabolism of living things. Four of these elements (hydrogen, carbon, nitrogen, and oxygen) are essential to every living thing and collectively make up 99% of the mass of protoplasm. [1]

  5. Biochemistry - Wikipedia

    en.wikipedia.org/wiki/Biochemistry

    Just six elements—carbon, hydrogen, nitrogen, oxygen, calcium and phosphorus—make up almost 99% of the mass of living cells, including those in the human body (see composition of the human body for a complete list). In addition to the six major elements that compose most of the human body, humans require smaller amounts of possibly 18 more ...

  6. Hydrogen - Wikipedia

    en.wikipedia.org/wiki/Hydrogen

    Therefore, steam reforming typically employs an excess of H 2 O. Additional hydrogen can be recovered from the steam by using carbon monoxide through the water gas shift reaction (WGS). This process requires an iron oxide catalyst: [110] CO + H 2 O → CO 2 + H 2. Hydrogen is sometimes produced and consumed in the same industrial process ...

  7. Triatomic hydrogen - Wikipedia

    en.wikipedia.org/wiki/Triatomic_hydrogen

    Triatomic hydrogen or H 3 is an unstable triatomic molecule containing only hydrogen. Since this molecule contains only three atoms of hydrogen it is the simplest triatomic molecule [1] and it is relatively simple to numerically solve the quantum mechanics description of the particles. Being unstable the molecule breaks up in under a millionth ...

  8. Hydrogen atom - Wikipedia

    en.wikipedia.org/wiki/Hydrogen_atom

    Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. (Image not to scale) A hydrogen atom is an atom of the chemical element hydrogen.The electrically neutral hydrogen atom contains a single positively charged proton in the nucleus, and a single negatively charged electron bound to the nucleus by the Coulomb force.

  9. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    For example, molecules of water (H 2 O) contain atoms of hydrogen (H) and oxygen (O), so water can be said as a compound consisting of the elements hydrogen (H) and oxygen (O) even though it does not contain the chemical substances (di)hydrogen (H 2) and (di)oxygen (O 2), as H 2 O molecules are different from H 2 and O 2 molecules. For the ...