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Q & A: attracting gold with magnets?

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Most recent answer: 08/28/2012
Q:
Why can't we create a magnet that can attract gold/gold atoms?
- Randomguy123 (age NA)
Do not wish to enclose
A:
Metallic gold is weakly diamagnetic, meaning that is is slightly repelled by magnetic fields. The reasons for diamagnetism are purely quantum mechanical, and perhaps too hard to explain here.

Individual gold atoms have an odd number of electrons, which means that they are a bit paramagnetic. That means they are attracted to magnetic fields, on average. However, if you make a rough estimate of the magnitude of the effect, you'll find that it isn't very useful. Say the magnetic moment is a few Bohr magnetons, about 10-20 emu. A  strong electromagnet will have a field of about 104 Oersted. That means that the energy with which the atom would be held in the field (the product of the field and the moment) would be a few times 10-16 ergs, Just plain thermal rattling at room temperature gives an energy of around 4*10-14 ergs. So the atoms would just rattle out of the magnetic trap.

Mike W.

(published on 08/28/2012)

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