Why do the Na ions safely reside in the water whereas Na does not?
Robert,
Good questions are always welcome. The answer to this is chemistry, i.e.
sodium wants to get ride of its valence electron and the hydrogen atoms in
water are happy to accept it. Thus the hydroxyl ions and the sodium ions
are left in solution. Please excuse the anthropomorphizing of atoms. In the
case of salt it is the chlorine ion and not the hydrogen one that end up in
solution.
Dissolving one substance in another is an equilibrium process. In the case
of sodium metal it breaks down the water giving off hydrogen gas thus
leaving the sodium ion behind with the hydroxyl group from the water. In
the case of salt the sodium and chlorine atoms dissociate and drift off. In
both cases it is the strongly dipolar water molecules that motivates the
change.
I hope this helps.
Gary
Gary Karshner
St. Mary's University
San Antonio, Texas
KARSHNER@STMARYTX.EDU