atom

[cameronthegreat]

This is more a question then anything but is it true that an atom is mostly full of nothing and the electrons whizzing round are like a few flies inside a chapel?

[ajb]

In sort, yes.

[cameronthegreat]

Thankyou, I thought this was the case.

[Enthalpy]

The electrons have the volume of the atom itself. I don't imagine them as points. So I don't say that an atom is void.

 

By the way, it's not what you'll hear most often, but I have good company in that representation of particles. Schriffer (from BCS) said it exactly the same way: the electron IS the wave (in the case of an atom, this wave is an orbital) and HAS that size, which depends on its state.

[Schneibster]

Just to complete the picture, the flies are circling a piece of neutron star that takes up only a tiny space compared to the rest of the atom; if the electrons are flies in church the neutron star is the size of your fist. And that fist is where all of the mass of the atom is.

[Wso]

I'll try to further help out our idea of an atom. The electrons, as all particles, can be waves. As particles however they are almost entirely perfectly spherical. The electrons are quite far from the nucleus compared to their size...most of the time. Due to the uncertainty of where the electrons are, they generally stay near their orbitals, but sometimes are actually inside the nucleus (I might be wrong here but this isn't this called quantum tunneling?). The protons and neutrons are made up of quarks, which are made up of strings, which, as far as we know now, are the smallest anything can be divided into. The distance between electrons is difficult to say because they are not fixed to one place at any one time. There is lots of "empty" space in between the various particles making up atoms. I say "empty" in quotes because empty space is teeming with virtual particles. I don't know the size of these virtual particles so maybe someone else will correct me here if I'm wrong, but these virtual particles make it impossible to say that there is truly empty space. If I was mistaken on anything here please correct me, hope this reply helped.

[Enthalpy]

The electron is considered elemental so it wouldn't have a shape.

 

What do you call the size of an electron? If you try to locate it precisely, it is smaller than any method humans have found up to now to measure it, so it's qualified by "point-like". In that sense, one couldn't compare it with a basket ball of a bee if zooming in the atom - it would remain a point at any magnification.

 

Though, I see no reason to attribute to the electron any other size than the wave, which can be small or big depending on the context. I just say (and I'm not alone) that in an atom, the electron (pair) is the orbital, so inner electrons are a bit smaller than the atom, outer electrons as big as the atom - or a few atoms in a molecule.

 

Some electrons, the S orbitals, have their maximum probability density right on the nucleus, so they need no tunnelling. These are the ones absorbed in a radioactive decay mode called electron capture.

 

Strings are one theory which predicted new particles that have not been observed, especially not at the LHC yet. As such, this theory deserves full language caution.

 

Orbitals, which I don't distinguish from electrons, are immobile. One calls them "stationary". That's why they don't radiate - only transitions between them do. Being immobile (but having an extension, or being "fuzzy" if you prefer) they could lead to some definition of a fixed distance - but said distance will depend on how one defines it. The electrostatic energy would make one such definition.

 

Saying that the electron (pairs) are orbitals, I see no vacuum at all in the atom. The atom is completely filled with the electrons. Though, if one tries to locate more finely the electrons, he will find one only from time to time.

 

Virtual particles have the size of the wave, which depends on the particle's (missing) energy and rest mass. One can define better the size of a particle if it's composite like an atom nucleus, but these are highly unlikely as virtual particles: only the lightest ones have significance.

 

One fundamental choice in the representation of particles is whether you want to imagine them as permanent points whose position is uncertain and determined by a wavefunction, or as being the wave, which carries some undivisible properties (charge, spin...) which are accounted for through an integer number of particles, and which can change its shape and size depending on the context.

[swansont]

Some electrons, the S orbitals, have their maximum probability density right on the nucleus, so they need no tunnelling. These are the ones absorbed in a radioactive decay mode called electron capture.

 

The probability is nonzero there, so you get the possibility of decay and also large hyperfine splitting, but it's not a maximum at (or near) r=0. The Bohr radius, which is the most probably radius for the electron in Hydrogen, is 52.9 pm. (nuclei are of order fm across, i.e. 10^-15m)

 

http://www.chem1.com/acad/webtext/atoms/atpt-images/s-orb_shells.png

[Enthalpy]

If you compute the probabilty density per volume unit, all S orbitals have the maximum at the nucleus.

 

If you compute the probability density per radius unit, the maximum is not at the nucleus.