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The human body, or for that matter, a body of any living organism is made out of...

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Rocky52 | Student, Undergraduate | (Level 2) Honors

Posted May 31, 2013 at 8:26 PM via web

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The human body, or for that matter, a body of any living organism is made out of tissues and each tissue is made from specific cells. Each cell is some sort of colony of smaller various types of molecules. Each molecule consists of atoms and each atom consists of two essential parts, an atomic nucleus where most of atomic mass is concentrated and electrons that surround it. For definiteness, let us assume a typical human. Estimate what fraction of a mass of typical human can be attributed to electrons.

 

*some guidance one this would be great!

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justaguide | College Teacher | (Level 2) Distinguished Educator

Posted June 1, 2013 at 4:34 AM (Answer #1)

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Atoms of all elements, except hydrogen, are made of electrons, neutrons and protons. The mass of a neutron and a proton can be considered to be the same and is equal to 1.672621777*10^-27 kg. The mass of an electron is 9.10938291*10^-31 kg. The ratio of the mass of neutrons or protons and that of electrons is approximately 1835. In an atom with one electron and one proton, the fraction of mass contributed by the electron is approximately 1/1836.

The human body is made of many elements and the number of elementary particles in each of them is different. This changes the fraction of mass contributed by electrons in each atom. If an assumption is made that the human body consists only of hydrogen atoms, the fraction of mass contributed by electrons is close to 1/1836. If atoms of other elements are taken into consideration the fraction is even lower as in each atom though the number of protons and electrons is the same the neutrons are not accompanied by electrons.

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