Galvanic cell and charge separation

Hello,
I was reading about galvanic cell. On the anode side the zinc is losing electrons and on the cathode side the cupper is gaining electron. We put salt bridge, to maintain the neutrality of the solution i.e SO4 2- will move to anode side and Na+ to the cathode side. Does an electric field cause their movement? or it is a diffusion current of the ions? When there's no wire connecting anodes and cathodes, is there electrons on the anode side? Thus having charge separation and voltage? Is there also a small charge separation during a closed circuit?

Thank you

This entry passed through the Full-Text RSS service - if this is your content and you're reading it on someone else's site, please read the FAQ at http://ift.tt/jcXqJW.

Galvanic cell and charge separation