Why Do Electrons Determine Atom Volume While Nucleons Account for Mass?

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    Atom Mass Volume
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Discussion Overview

The discussion centers on the relationship between electrons and nucleons in determining the volume and mass of an atom. Participants explore the conceptual framework behind why electrons are associated with atomic volume while nucleons account for atomic mass, touching on analogies and the implications of these distinctions.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant questions why electrons determine atomic volume while nucleons account for mass, seeking clarification on this relationship.
  • Another participant draws an analogy between atomic structure and the solar system, suggesting that just as the solar system's volume is influenced by the outer planets, atomic volume is influenced by the electrons, while mass is dominated by the nucleons.
  • A participant provides specific mass values for protons, neutrons, and electrons, highlighting the significant mass difference, which supports the idea that the nucleus primarily contributes to atomic mass.
  • There is a humorous remark about not asking why, indicating a light-hearted approach to the complexity of the topic.

Areas of Agreement / Disagreement

Participants express differing views on the appropriateness of analogies used to explain atomic structure, and while some points are clarified, there is no consensus on the underlying reasons for the distinctions between volume and mass contributions.

Contextual Notes

The discussion includes approximations and analogies that may not fully capture the complexities of atomic structure. There are also references to historical understanding and experimental findings that may influence current interpretations.

burgess
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The Volume of an atom comes from its electrons and mass of an atom comes from its nucleons. I don't understand why?

Any one can explain it please?

Thanks in advance
 
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because the "volume" of the solar system comes from pluto's trajectory (when it was the last planet), while its mass comes from the Sun...
The last statement is an approximation for the solar system because the mass of the sun is pretty much overpassing the masses of the rest planets. Of course there are pretty massive planets in the solar system as well (eg Jupiter) so it's an approximation.
Also for the case of atoms, of course you can't use the Solar System model, except for getting the idea of it. We know today that the nuclei have a radius of approximately 1 to some hundrends of fm (in the past what people knew was that the nuclei existed in a very small region-condensed- within the atom by Rutherford's experiment)... The average radius of an electron's existence in the atom (the distance in which you are pretty sure up to 99% the electron will exist) is of the order of 1-100 nm ...
So the radius of the atom would be given by the last.
For the case of electrons though, they all have the same mass, but it's still very much lighter than the mass of a proton
(~10- 3~4 orders of magnitude less)
So the protons' masses overwhelm the electron masses, so approximately you can say that the atom's mass is given by the nucleus...
Of course that's not really true- you have to take into account the masses of electrons sometimes (eg in nuclei decays)
 
Last edited:
Mass of proton : 1.672 621 777 x 10-27 kg +/- 0.000 000 074 x 10-27 kg
Mass of neutron: 1,6749 x 10^(-27) kg
Mass of electron: 0,00091x10^(-27) kg

To put that another way,

A Neutron weighs 1.
A Proton weighs 0.99862349.
Electrons weigh 0.00054386734 each.Still another way to say that is, a proton weighs about 1836.15 times as much as an electron. And a neutron weighs about as much as 1838.7 electrons.

Please don't ask why.
 
Last edited:
Frosted Flake said:
Please don't ask why.

Couldn't help but grin for a minute.
 

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