Fig 11A battery, opened upclick to pausezinc → copper
electronszinc ions leavecopper ions arriveZinc gives up electrons more readily than copper, so this cell runs one reaction in two halves. On the left, zinc atoms lose two electrons each and dissolve as zinc ions. The electrons can't cross the liquid, so they travel through the wire, doing work on the way, to the copper side, where copper ions in the solution pick them up and plate out as copper metal. The salt bridge lets ions drift between the beakers so that charge doesn't build up. Every battery works this way, with different metals or compounds.