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Re: Peroidic Table (was exclusion principle which was electrons)



Yeah I got it. atom not nucleus.
Showed my ignorance again................


At 02:04 PM 11/16/2003, you wrote:
Sorry, Charles. You are thinking of the nuclei, not the atoms.
The "shape" of an atom is determined by the angular momenta of the outer
electons, but it is not a bad first approximation to think of all atoms as
"round". You must pay attention to my "hint".



On Sat, 15 Nov 2003, Charles Bell wrote:

> Uranium atoms are football shaped, not round.
> I remember from the liquid drop model that Uranium and Plutonium and other
> transuranics are football shaped and that when they absorb a neutron they
> fission when the ends bulge out and form asymetrical smaller drops.
>
> Diameter might not be good parameter.
>
> At 11:33 AM 11/15/2003, you wrote:
> > It is always wise to examine the the truth of the facts that you
> >wish to explain. How does the diameter of a Uranium atom compare with the
> >diameter of a hydorgen atom.
> > Hint: to a good approximation, the density of most elements is
> >proportional to the atomic weight of the element.
> >
> >
> >
> >
> >On Sat, 15 Nov 2003, Craig Lucanus wrote:
> >
> > > Josh Green wrote:
> > > > shells are something we can "see" from atomic diameters. This would
> > > > eliminate the possibility of all the electrons filling in the first
> > shell,
> > > > since we know that the third electron fills in another
shell. This comes
> > > > not by theory, but by observation, which is explained by shells of
> > > different
> > > > levels.
> > >
> > > Why can't the observation of atomic diameters be explained by electrons
> > > spherically milling about the nucleus building outwards with
increasing
> > > population (up to 92 for the naturally occuring elements)? If, by
> > > observation, you really mean evidence for shells, like the changes
noted in
> > > successive ionization energies of an element, fine. But diameters?
Also, I
> > > disagree that we can 'see' shells or orbitals as these are
mathematical QM
> > > constructs.
> > >
> > > If electrons don't simply mill around the nucleus, but do form up in
> > shells,
> > > then what set of shell rules do they obey? We have devised a set of
> > > mathematical rules that seems to fit the observations of chemical
> > > properties, with a basis in numerology, if that's what you want to call
> > > quantum numbers, and a knowledge of the number of electrons in an
atom. The
> > > exclusion principle is one of the fundamental mathematical rules.
> > >
> > > Applying these rules requires a bit of jiggery- pokery too, like
> > starting to
> > > fill outer shells before inner ones are full, without any numerological
> > > (mathematical) basis for doing so, only knowing that it is a necessary
> > > proposal if the mathematical rules are to fit the observed
properties of
> > > elements. Nobody has determined, ab initio at least, why this
should occur,
> > > be it from a consideration of atomic number only, or using any of the
> > > quantum numbers associated with atomic theory.
> > >
> > > Nuclear charge (hence Z) only partly determines the potential
energy of an
> > > electron in a multi-electron atom (albeit that it determines the
number of
> > > electrons in the case of a neutral atom, and thus is of arithmetical
> > > consequence only). Perhaps if we had a full mathematical
understanding of
> > > such atoms instead of the approximation based on the H-atom we are
> > currently
> > > stuck with, and if the exclusion principle was then found to be a
direct
> > > consequence of atomic number, then Josh would have an argument.
Somehow, I
> > > think the basic premise that no two electrons can occupy exact same
energy
> > > states would be a part of any new theory, and would simply have to be
> > > accepted as it is now, with no real understanding of why it has to be.
> > >
> > > Perhaps the last sentence touches more on the original question
posed by
> > > Josh about electrons.
> > >
> >
> >--
> >"Don't push the river, it flows by itself"
> > Frederick Perls
>

--
"Don't push the river, it flows by itself"
Frederick Perls