Galvanic Cells

[Murphy Brown]

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Don't galvanic cells have a negatively charged anode? Why is it that anions flow toward the anode instead of the cathode if they're anions?

 

[rocuronium]

Galvanic anodes are called 'negative' because they are the source of electrons (i.e. electrons move away from the anode), not because of a negative polarity.

It is by definition that anions move toward the anode and cations move toward the cathode. This is true in any type of electrochemical cell.

 

[Murphy Brown]

Thank you. I did not know that.

 

[futuredoctor10]

It is by definition that anions move toward the anode and cations move toward the cathode. This is true in any type of electrochemical cell.

Also for any electrochemical cell, know electrons move from ANODE to CATHODE.
(And AnOx RedCat - oxidation @ anode, reduction @ cathode - is true for all electrochemical cells as well)

It seems odd that electrons move from anode to cathode, yet cations (+ charge) move toward the cathode. This from wikipedia helps explain:

Michael Faraday defined the cathode as the electrode to which cations flow (positively charged ions, like silver ions Ag+), to be reduced by reacting with (negatively-charged) electrons on the cathode. Likewise he defined the anode as the electrode to which flow anions (negatively charged ions, like chloride ions Cl-), to be oxidized by depositing electrons on the anode. Thus positive electric current flows from the cathode to the anode.

 

[FutureScaresMe]

This may be the completely wrong way to think of it, but it has helped me. I think of the anode as having a negative core, repelling electrons away from it. But if electrons are leaving, then something needs to become positve, the outer layer, causing anions to attract. Opposite for cathode, positive core attracting electrons which cause a negative outer layer, thus cation attraction