Why do atoms want a full outer shell
Isn't this more of a description of what happens, rather than an explanation? I would now like to give a far better answer...... but sadly I can't think of one!Originally posted by benzun_1999
the answer for your question is simple.
To attain stable electronic configuration they they try to have full the outermost orbit or valence orbit.This is done by losing or gaining electrons.
My understanding is that the label +- 1/2 is just to remind us that there are only two possibilities. They are often called up and down and could have been called left and right but +- 1/2 stuck.Originally posted by Chi Meson
All subatomic particles have a spin quantum number. Electrons have either a + or - 1/2 spin. Half-integer spin is a characteristic of those particles that we think of as "material," "stuff," etc. neutrons and protons also have 1/2 interger spins. THis stuff obeys a certain set of quantum rules.
The 1/2 and -1/2 are more than just names.Originally posted by mmwave
My understanding is that the label +- 1/2 is just to remind us that there are only two possibilities. They are often called up and down and could have been called left and right but +- 1/2 stuck.
(1) A half filled shell is stable? I guess you could say it's stable, in the same sense that every nonradioactive atom has a stable configuration, regardless of how full or empty the valence shell is. Iron "turns into" rust because it prefers a "full" valence shell, regardless of how "stable" it is as atomic iron. I think the question is more, "why do atoms want to fill their shells the way they do?" not, "why is a full valence shell a stable configuration?"Originally posted by futz
The reason why a full shell is more stable is more or less the same reason a half-filled shell is stable.
There are a set of guidelines called Hund's Rules which are used to determine the ground state electron configuration of a particular atom.
The underlying principle is that electrons fill orbitals in such a way as to minimize the total energy of the atom. ... the atom wants to have the largest number of parallel spins that it can ... The reason for this is as follows: two spins that are parallel "don't like each other", so they will tend to push apart. This decreases the Coulomb energy between them, lowering the overall energy ...
... to fully detemine the electron configuration, we need to apply the rest of Hund's rules (2 of them), which are more complicated, and break down for certain elements.
(1) Alright, I'll buy that.Originally posted by futz
(1) By stable, I simply meant it is generally more stable than certain other configurations, say half filled plus 1.
(2) The 1s subshell (n=1, l=0) can hold two electrons. Once the first one goes in, the second has no choice but to go in antiparallel to the first. Energy is still minimized, even though the spins aren't parallel (usually, electrons will fill one subshell before moving onto another, at least in this case).
(3) By the way, all 3 rules are based on minimization of energy: ...
Not to nitpick (sp?), but "Minimization of energy" is never a driving force. In this case there are mainly electromagnetic forces, which have to play in the stage set by the quantum rules. We call "energy" a number that is defined to be minimum when nothing further can be extracted from the system. If the system is such that it spontaneously "goes" to a different state, then we were not in the minimum yet.Originally posted by futz
Whether or not min. of energy is the only force behind the electron's behavior, I guess I honestly don't know. All of my courses listed it as such . [/B]
An unbalanced atom would be one that has become ionized by losing an electron form an outer shell. Thus it is ELECTRICALLY unbalanced. It has nothing to do with the location of the center of mass, which is what unbalanced refers to in the macro world. The nucleus which accounts for virtually all of the mass of atom but a fraction of the volume determines the center of mass.Originally posted by barcat
I need to ask. Is there really such a thing as and unbalanced atom? If there is, is this the reason for "Brownian Motion"?