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Name: Bethany
Status: student
Age: 12
Location: N/A
Country: N/A
Date: 2000-2001

Is it possible to add a proton to an atom? What would happen? Considering that the atom would then have one fewer electrons that protons, would it not become an ion?

Yes, it is possible, and if nothing lse happened you would have produced a positive ion. Usually, though, what you produce is an unstable nucleus that has lost an electron or so.

First, the electrons: It's jarring for an electron to suddenly find itself associated with a nucleus with more charge than the one they had settled into. As they settle into new "orbits" some electrons might acquire enough energy to break free of the nucleus.

Second, the nucleus: There's a war going on, in nuclei, between the attractive short-range nuclear force that holds protons and neutrons together and the repulsive electromagnetic force between protons. Nuclei with too many protons are unstable and break into fragments.

Also, it takes a little extra energy to get a proton into the nucleus. Since the repulsive electromagnetic force is longer range than the attractive nuclear force, a proton almost but not quite touching the nucleus feels only the repulsive force. You have to give the proton extra energy to shove it in, and then when it settles, it has more energy than it needs. Somehow, the nucleus must get rid of this extra energy. One way is to spit out some other particle.

Tim Mooney

Tha hard part would be getting iot to happen. A proton would be repelled by the atom's positively-charged nucleus. You would have to fire the proton right at the nucleus very fast to get past this repulsive force. Once it got close enough, the "strong force" that holds the nucleus together (did you ever wonder what makes all those positively-charged protons clump into a ball?) could hold on to it.

Once that were accomplished, you are right, the atom would be an ion, because the number of electrons and protons would not be equal. The nucleus itself might also be unstable. That of course depends on how many protons and neutrons were in the nucleus before the proton was added.

Richard E. Barrans Jr., Ph.D.
Assistant Director
PG Research Foundation, Darien, Illinois

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