Can a piece of metal have all of its conduction electrons stripped? If so, has this been done and for what value?
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$\begingroup$ What would be the net charge if you did this for a 1 gram piece of copper? Does this seem possible? $\endgroup$– Bill NCommented Sep 29, 2015 at 20:48
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1$\begingroup$ What do you mean "...and for what value?"? $\endgroup$– DanielSankCommented Sep 30, 2015 at 6:49
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$\begingroup$ What value would stripping electrons have, in a real-world scenario - physics or engineering say. $\endgroup$– ImaiCommented Sep 30, 2015 at 21:41
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2 Answers
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It depends on what exactly you are asking.
Suppose we take 64g of copper i.e. one mole of copper. Each copper atom contributes one conduction electron, so our chunk of copper contains $6.023 \times 10^{23}$ (Avagadro's number) conduction electrons with a total charge of 96488 coulombs.
John's answer involves removing those electrons by a chemical reaction. For example if you react the copper with a mole of chlorine you get a mole of copper (I) chloride. The conduction electrons have been removed by transferring them to chlorine atoms. If your question allows this interpretation then yes indeed you can remove all the conduction electrons, though the end result is a new chemical, copper chloride, rather than copper metal without any conduction electrons.
The other interpretation is to use something like the photoelectric effect to remove the conduction electrons. If you shine uv light onto the copper block the light will start ejecting electrons leaving the copper with a positive charge. The trouble is that to remove all the electrons would require an absurdly large amount of energy. Suppose our piece of copper is a sphere, then the energy required to produce a charge $Q$ is given by:
$$ E = \tfrac{1}{2} \frac{Q^2}{C} $$
The self capacitance of a sphere with radius $r$ is:
$$ C = 4\pi\varepsilon_0r $$
Since the density of copper is 8960 kg/m$^3$, the radius of our 64g of copper is about 1.2cm. Putting this into the equation above we get:
$$ E \approx 3.5 \times 10^{21} \text{J} $$
The voltage is given by $V = Q/C$, and this works out to be about 73000 teravolts.
So if this is the correct interpretation of your question then no you cannot remove all the conduction electrons from the copper.
answered Sep 30, 2015 at 7:12
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$\begingroup$ 73000 teravolts, LOL! One Don't go near it Bill! That's definitely worth a brownie point. $\endgroup$ Commented Sep 30, 2015 at 7:21
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Can a piece of metal have all of its conduction electrons stripped?
Yes.
If so, has this been done
Yes.
and for what value?
I'm sorry, I don't know what you mean by that. But one example of the thing you're asking about is electrolysis. Check out things like galvanic corrosion and sacrificial anodes.
answered Sep 29, 2015 at 19:29
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2$\begingroup$ Are you sure all of the conduction electrons have been stripped? Your references really don't address this. $\endgroup$ Commented Sep 29, 2015 at 20:07
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$\begingroup$ Yes, the metal takes the forms of ions. There's other electrons within those ions though. See this re first second and third etc ionization energies. $\endgroup$ Commented Sep 29, 2015 at 20:09
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1$\begingroup$ I think the OP was wondering if a block of metal, in situ, could have all its conduction electrons removed. $\endgroup$ Commented Sep 29, 2015 at 20:23
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$\begingroup$ @Daniel Griscom : maybe, but then you've got a lump of positive ions, and the Coulomb force is pretty huge. $\endgroup$ Commented Sep 29, 2015 at 20:44
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$\begingroup$ Take 1 gram of copper and strip 1 electron from each atom without replacement. You now have a small piece of copper with a charge of 1500 coulombs. Sounds unreasonable to me. $\endgroup$– Bill NCommented Sep 29, 2015 at 21:56