Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
Re: A simple chemistry question...
0 views
Skip to first unread message
Y.Porat
Dec 30, 2009, 9:41:05 AM12/30/09
to
On Dec 30, 7:03 am, "hhc...@yahoo.com" <hhc...@yahoo.com> wrote:
> On Dec 28, 5:55 am, Sam Wormley <sworml...@gmail.com> wrote:
>
>
>
> > On 12/28/09 2:29 AM, hhc...@yahoo.com wrote:
>
> > > On Dec 26, 7:37 pm, Sam Wormley<sworml...@gmail.com> wrote:
> > >> On 12/26/09 6:10 PM, chutsu wrote:
>
> > >>> I know this is a physics newsgroup, but should be able to answer this
> > >>> question anyways.
>
> > >>> My question is, why are all atoms neutral? Apart from it has equal
> > >>> amounts of electrons and protons.. like why or how do we know that
> > >>> atoms in the periodic table is neutral?
>
> > >>> Thanks
>
> > >> They aren't. Most of the atoms in stars are stripped of electrons.
> > >> The electromagnetic force is very strong and tends to make low
> > >> energy atoms neutrally balanced charge-wise.
>
> > >> Google is your friend
> > >> http://en.wikipedia.org/wiki/Atom#Electron_cloud
>
> > > Sam, not to be pedantic, but an atom stripped of an electron or with
> > > an added electron is an "Ion", an atom with a polarity..
>
> > > All atoms are electrically neutral to fit the definition of an atom.
> > > For the original poster an alpha particle is a helium nucleus,not an
> > > atom.
> > > Similarly, a proton is a hydrogen nucleus, not an atom.
>
> > > You can put an electrical charge on an aluminum pan, but that does't
> > > alter its atomic structure...it's still aluminum.
>
> > > Harry C.
>
> > Thanks Harry, I agree. However, astronomers identify
> > their atoms by the spectral lines, and seldom add the
> > word "ion".- Hide quoted text -
>
> > - Show quoted text -
>
> Sam, quite true, but that is not the question that the OP asked.
>
> Again, not to be pedantic, but spectral lines are the characteristics
> of elements, not atoms. They amount to the same thing, with an
> important difference. Spectral lines are associated with the excited
> nucleus of an element, and incorrectly sometimes called atomic
> spectra. The atomic spectra has nothing to do with the electrons that
> surround an atom and render it neutral. They are entirely based on the
> nucleus of the atom itself.
>
> I remember this because as an undergraduate I did my research project
> in optical emission spectography. This is rather dated technology
> today, but it provides a foundation for more advanced work.
>
> The experimental procedure here is to "burn" a sample of some material
> in a spectrographic arc (simply 2 sticks of carbon with a cavity to
> hold a sample). The electric arc removes the electron layers in a
> fraction of a second, and what remains giving off electromagnetic
> radiation is the nucleus of the atom, not the atom itself. This
> electromagnetic radiation (bright line specta or atomic spectra) is
> passed through either a prism or grating and recorded on a
> photographic plate. On analysis, the lines on the plate reveal the
> identity of the element that produced them.
>
> What I did not mention is that in spectrographic analysis, a sample of
> iron is usually burned first, since the what are called the critical
> lines of the iron spectra are well known and documented. Then, the
> photographic plate is indexed upward and the sample is burned. This
> permits comparison of the spectral lines of the sample to be compared
> with those of iron, which serves as a yardstick, so the lines in the
> sample can be compared with those of iron and, once known, can be
> looked up in a book called the International Critical Tables.
>
> Astronomers use precisely the same method, plus a little trial and
> error in their calibrations.
>
> Remember, I am recalling all of this from around 1957, but it should
> be close enough for government work.
>
> Harry C.
> On Dec 28, 5:55 am, Sam Wormley <sworml...@gmail.com> wrote:
>
>
>
> > On 12/28/09 2:29 AM, hhc...@yahoo.com wrote:
>
> > > On Dec 26, 7:37 pm, Sam Wormley<sworml...@gmail.com> wrote:
> > >> On 12/26/09 6:10 PM, chutsu wrote:
>
> > >>> I know this is a physics newsgroup, but should be able to answer this
> > >>> question anyways.
>
> > >>> My question is, why are all atoms neutral? Apart from it has equal
> > >>> amounts of electrons and protons.. like why or how do we know that
> > >>> atoms in the periodic table is neutral?
>
> > >>> Thanks
>
> > >> They aren't. Most of the atoms in stars are stripped of electrons.
> > >> The electromagnetic force is very strong and tends to make low
> > >> energy atoms neutrally balanced charge-wise.
>
> > >> Google is your friend
> > >> http://en.wikipedia.org/wiki/Atom#Electron_cloud
>
> > > Sam, not to be pedantic, but an atom stripped of an electron or with
> > > an added electron is an "Ion", an atom with a polarity..
>
> > > All atoms are electrically neutral to fit the definition of an atom.
> > > For the original poster an alpha particle is a helium nucleus,not an
> > > atom.
> > > Similarly, a proton is a hydrogen nucleus, not an atom.
>
> > > You can put an electrical charge on an aluminum pan, but that does't
> > > alter its atomic structure...it's still aluminum.
>
> > > Harry C.
>
> > Thanks Harry, I agree. However, astronomers identify
> > their atoms by the spectral lines, and seldom add the
> > word "ion".- Hide quoted text -
>
> > - Show quoted text -
>
> Sam, quite true, but that is not the question that the OP asked.
>
> Again, not to be pedantic, but spectral lines are the characteristics
> of elements, not atoms. They amount to the same thing, with an
> important difference. Spectral lines are associated with the excited
> nucleus of an element, and incorrectly sometimes called atomic
> spectra. The atomic spectra has nothing to do with the electrons that
> surround an atom and render it neutral. They are entirely based on the
> nucleus of the atom itself.
>
> I remember this because as an undergraduate I did my research project
> in optical emission spectography. This is rather dated technology
> today, but it provides a foundation for more advanced work.
>
> The experimental procedure here is to "burn" a sample of some material
> in a spectrographic arc (simply 2 sticks of carbon with a cavity to
> hold a sample). The electric arc removes the electron layers in a
> fraction of a second, and what remains giving off electromagnetic
> radiation is the nucleus of the atom, not the atom itself. This
> electromagnetic radiation (bright line specta or atomic spectra) is
> passed through either a prism or grating and recorded on a
> photographic plate. On analysis, the lines on the plate reveal the
> identity of the element that produced them.
>
> What I did not mention is that in spectrographic analysis, a sample of
> iron is usually burned first, since the what are called the critical
> lines of the iron spectra are well known and documented. Then, the
> photographic plate is indexed upward and the sample is burned. This
> permits comparison of the spectral lines of the sample to be compared
> with those of iron, which serves as a yardstick, so the lines in the
> sample can be compared with those of iron and, once known, can be
> looked up in a book called the International Critical Tables.
>
> Astronomers use precisely the same method, plus a little trial and
> error in their calibrations.
>
> Remember, I am recalling all of this from around 1957, but it should
> be close enough for government work.
>
> Harry C.
seems right
but still alot to learn:
no existing theory can explain
the complete spectrum of a heavy Atom!
certianly not if it is based on
'the number of protons in the nuc= equal to the number of electrons
'around it' !!
2
see the 'chain of orbitals idea:
it is about the connection between
heavy orbitals (of the nuc mediating orbitals )and lighter orbitals -
the electrons
all of them connected in one * linear chain *
ATB
Y.Porat
-----------------------
0 new messages