[professorv (OP)]

If happen a atom to get very close the velocity "c" the time will almost
stop.
What will happen to the velocity of the orbit and spin of a electron? It
will slow down too?

[Phractality]

In mainstream physics, the electron is widely believed to be a fundamental particle. If that is so, it has not constituent parts by which to count time. The term "spin" in the standard model of particle physics is misleading; it has nothing to do with parts moving around a center.

In my own model (globe icon to left of this post), any particle with rest mass consists of orbiting photons; only the photons are fundamental. So the photons continue to orbit at the speed of light around their common center. If the center is moving relative to some reference frame, then the photons have farther to go per orbit and take longer to complete each orbit in that reference frame. In the reference frame whose origin is the center of the particle, the orbits are not slowed down.

[professorv (OP)]

I don't know if i understood this, if spin is not a real spin movement, how this experiment can work with electrons?

newbielink:https://en.wikipedia.org/wiki/Stern%E2%80%93Gerlach_experiment [nonactive]

[imatfaal]

Prof Vee - spin is described as instrinsic angular momentum, but it is definitely NOT the particle spinning like a top.  It is a subtle and non-entirely rationalisable idea - wikipedia has a fair page on it here and hyperphysics here

Spin was introduced to fill the gap of another number needed to parametise the electron - and it does have remarkable similarities to a simple spinning object, however it has differences as well.  It is quantised, it is intrinsic and cannot be changed for a fundamental particle, and as your first question notes it isnt "real" otherwise you could get past c. 

You can read up on basic quantum mechanics and spin quantum number which might help you get a handle on things - but do not imagine that you can have a valid real-world picture in your head of this stuff, it just does not admit to simple human analogies

[vlassius]

Hi, interesting question. I think that the electron will get still if the atom get c.
This has nothing to do with velocity but time.
I think when approaches the c velocity, the velocity in orbit will be the same, just the time will be dilated so, the orbit would not be affected. If we take from another frame of reference (not the atom itself) moving in a low velocity comparing with c, the electron would still running normally in orbit.
But i think that it will really get still when the atom gets the c velocity, really stopped still in orbit like a snapshot.
This gets more interesting if we think that it is related with the conduction of electricity. The electron needs to change from atom to atom to get a current. If the electron is still in orbit, the material that has this atoms, could not be conduct electricity.
We are talking about transistors, or semi-conductors, metals, etc... If it gets c velocity, the materials that we knows would stop to conduct electricity