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The Spatial Structure of an Atom

Atoms consist of nuclei and shells of electrons. However their nuclei take up just a small amount of the space surrounded by the elctronic shells. The purpose of this material is to document the magnitudes involved and display a visual depiction of the spatial structure of an atom.

An atom of hydrogen will be used for this purpose. The complication is that under normal conditions hydrogen does not exist as single atoms but instead as diatomic molecules, H2.

The proton has a mass nearly 2000 time that of an electron, so effectively an electron revolves around the center of the proton.

The appropriate unit of length for this analysis is the fermi, 10−15 meter. The radius of a proton is about 0.88 fermi. If an electron has the same mass density as a proton then its radius is about 0.072 fermi.

The smallest orbit in a hydrogen atom, the so-called Bohr radius, is

5.29x10−11 = 5.29x104x10−15 = 52900x10−15 = 52,900 fermi.

That length is over 30 thousand times the width of a proton and almost 370 thousand times the width of an electron. Thus in any visual depiction of a hydrogen atom the proton and electron are imperceptible.

An electron in a hydrogen atom revolves around the proton 6.56x1015 times per second. Thus the dynamic appearance of an electron is as a very thin torus. Therefore this is what a hydrogen atom would look like.


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