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Resistivity: A Question

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ninjakannon
I've been doing some research for some work I have and - as far as I can tell - the more reactive a metal is, the greater its resistance (Ω) is when an electric current is passed through it.
Wikipedia's page on resistivity provides the table of resistivities, some formulae and a bit of information about how temperature affects resistivity but does not explain why more reactive metals are more resistant, it is this I need to know.

I would be very obliged if anyone could explain this to me, or give me a link [or a few links] to help me.

Thanks a lot.
Indi
ninjakannon wrote:
I've been doing some research for some work I have and - as far as I can tell - the more reactive a metal is, the greater its resistance (Ω) is when an electric current is passed through it.
Wikipedia's page on resistivity provides the table of resistivities, some formulae and a bit of information about how temperature affects resistivity but does not explain why more reactive metals are more resistant, it is this I need to know.

I would be very obliged if anyone could explain this to me, or give me a link [or a few links] to help me.

Thanks a lot.

i've never heard about this relationship before. It certainly warrants further research.

i can offer a seat-of-the pants hypothesis, though. More reactive materials are more reactive because the bonds that hold the atoms together are weaker. Weaker bonds mean that the atoms will vibrate more with respect to each other for a given amount of energy. In the case of a metal, that means that the atoms in the crystal lattice will shake more easily, which means they have a slightly larger effective radius (basically the same thing that happens when the metal is heated). That means more impacts with the flowing electrons, which means more resistance to current.

An interesting further implication to explore would be that the rate at which resistivity increases with temperature should be higher for more reactive metals. Does that hold?
dooble.doodles
How are you defining the reactivity of the metal? Or non-metal?

I usually worry about galvantic differences... usually between conductors. If the differences are to great, you get lovely reactions. Sad

Silver and Copper react quite nicely with many things. Often with things that you don't want them to. I know the chemicals in the air in different areas will leave circuit boards with interesting reactions.

I think it's not easy to provide a decent response unless material reactivity is defined.
dooble.doodles
How are you defining the reactivity of the metal? Or non-metal?

I usually worry about galvantic differences... usually between conductors. If the differences are to great, you get lovely reactions. Sad

Silver and Copper react quite nicely with many things. Often with things that you don't want them to. I know the chemicals in the air in different areas will leave circuit boards with interesting reactions.

I think it's not easy to provide a decent response unless material reactivity is defined.
ninjakannon
dooble.doodles wrote:
How are you defining the reactivity of the metal? Or non-metal?

Oh, sorry I didn't include that. I'm using the reactivity series to determine how reactive each metal is - I am only investigating metals for this too.

Indi, your hypothesis sounds plausible although I'm not sure whether it's correct.

Anyone else have any idea?

EDIT:
I have concluded my views on this in the following paragraph, although I'm not 100% on it.

I believe the relationship between reactivity and resistivity is direct: the more reactive the metal is, the greater its resistance; I shall explain why I think this. The bonds in more reactive elements are weaker (as the outer shell of electrons is less full and forces are such that the outer shell 'wants' to be full), because of this they vibrate more; I would assume that this vibration is caused by forces acting on the electrons. As the bonds are weaker the electron(s) in the outer shell is/are more likely to be attracted by other forces – this being either positive magnetism or another atom 'wanting' a full outer shell. The atom's nucleus has a positive charge and will therefore pull the electron back in if it starts to move away (electrons have a negative charge), thus vibration is caused; this is only my hypothesis though. As the atom is vibrating more it fills a slightly larger effective area and thus more electrons will collide with the atoms in the metal as all the atoms will be vibrating similarly; this is again, however, only my hypothesis.
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