Cations and anions

[methodsboy]

hey guys
you know how they say "anions flow towards anode. cations flow towards cathode"? is that true for BOTH galvanic AND electrolytic cells?

or is it "anions flow towards -ve electrode and cations flow towards +ve electrode"?

[explode]

"anions flow towards anode. cations flow towards cathode"

That's right

[chem-nerd]

yes it's true for both, as oxidation always occurs at the anode (build up of positive charge) and reduction always occurs at the cathode (build up of negative charge)

[methodsboy]

okay thanks guys

[StringFever]

yes it's true for both, as oxidation always occurs at the anode (build up of positive charge) and reduction always occurs at the cathode (build up of negative charge)

Firstly I don't dispute the statement, I would just like some explanation because I'm a little confused.

I thought oxidation produced negatively-charged electrons. In saying so, then how is there a build-up of positive charge?!

[explode]

yes it's true for both, as oxidation always occurs at the anode (build up of positive charge) and reduction always occurs at the cathode (build up of negative charge)

Firstly I don't dispute the statement, I would just like some explanation because I'm a little confused.

I thought oxidation produced negatively-charged electrons. In saying so, then how is there a build-up of positive charge?!

The electrode or whatever is being oxidised will become a positively charged ion

eg
Cu -> Cu2+  +  2e-

so that's where the positive charge comes from. The anions are attracted to the oxidised species

[StringFever]

yes it's true for both, as oxidation always occurs at the anode (build up of positive charge) and reduction always occurs at the cathode (build up of negative charge)

Firstly I don't dispute the statement, I would just like some explanation because I'm a little confused.

I thought oxidation produced negatively-charged electrons. In saying so, then how is there a build-up of positive charge?!

The electrode or whatever is being oxidised will become a positively charged ion

eg
Cu -> Cu2+  +  2e-

so that's where the positive charge comes from. The anions are attracted to the oxidised species

Oh yeah, kinda forgot about that one! Whoops! :S

[methodsboy]

from wikipedia:
In an electrolytic cell, the cathode supplies electrons to the positively charged cations which flow to it from the electrolyte (even if the cell is galvanic, i.e., when the cathode is positive and therefore would be expected to repel the positively charged cations; this is due to electrode potential relative to the electrolyte solution being different for the anode and cathode metal/electrolyte systems in a galvanic cell).
so it works for both? can some one confirm?

[explode]

I think that's just saying the cations get reduced at the cathode. The simplest way to think of it is still probably "anions flow towards anode. cations flow towards cathode".

[chem-nerd]

yes it's true for both. Even though in a galvanic cell the cathode is labelled as the positive electrode it still has electrons flowing to it. The are accepted by the oxidant in that half cell and thus cause a build up of negative charge as cations are being consumed.