Re: Bohr's Atom still number one

The_Man <me_so_horneeeee@xxxxxxxxx> wrote in
news:1178648823.381018.297020@xxxxxxxxxxxxxxxxxxxxxxxxxxxx:

On May 8, 12:50 am, a...@xxxxxxxxxxxxxxxxxxx (John Park) wrote:
bz (bz+...@xxxxxxxxxxxxxxxxxxxx) writes:
The_Man <me_so_hornee...@xxxxxxxxx> wrote in
[...]
Core electrons travel at approximately c/ Z, where Z is the
nuclear charge. When Z gets large, the speed of the electrons
becomes sufficiently close to c, so that relativistic effects become
very important.

Are such effects observed? Wouldn't the atomic mass be effected?

Effects are observed in the chemistry of the very heavy elements.
Iodine, which seems just like a really massive version of chlorine,
has distrinct properties as a result of relativistic effects. These
can be calculated with either the Dirac-Fock method, or the use of
relativistic effective pseudopotentials.


[...]
I don't think the velocity is ~c/Z (proportional to sqrt (Z) maybe),
but relativistic effects are observed, though usually rather subtle.
They influence the energy levels of heavy atoms (where the core, high-Z
effect is important) and, I seem to recall, are responsible for gold
being yellow.

I stand corrected (I was typing off the top of my head)
The velocity of inner (core) electrons is (very) roughly100*Z/c, so
that the speed of inner core electrons for uranium is 92% c.

do you mean 100Z/c, or perhaps something like (100%/(110-Z)) * c?

Reference?

92%c gives a KE of 216,300 eV times however many electrons you consider
'inner core'(non relativistic). The longitudinal mass would be about 16.6
times the rest mass of an electron. Both seem a bit high to me. When I take
into account the increased mass, the KE of each core electron becomes 3.6
MeV.

The
formula is only vaguely acccurate - obviously, the electrons of
element 101 are not going faster than c. But it shows that
relativistic effects can't be ignored for very heavy elements (say Z
70).





--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.

bz+spr@xxxxxxxxxxxxxxxxxxxx remove ch100-5 to avoid spam trap
.

Relevant Pages

  • Re: Bohrs Atom still number one
    ... Effects are observed in the chemistry of the very heavy elements. ... has distrinct properties as a result of relativistic effects. ... The velocity of inner (core) electrons is roughly100*Z/c, ...
    (sci.physics.relativity)
  • Re: Bohrs Atom still number one
    ... nuclear charge. ... the speed of the electrons becomes ... relativistic effects are observed, though usually rather subtle. ... influence the energy levels of heavy atoms (where the core, ...
    (sci.physics.relativity)