-which one of these elements would be present at the cathode and at the anode?
-to complete such a voltaic cell, a salt bridge would be necessary between the anode and the cathode...what's the purpose of this salt bridge?
A reduction requires electrons so occurs at the cathode - tin reaction occurs ...
The expert examines lithium atoms being oxidized while tin ions are reduced. If these elements are present, the cathode and anode are determined. A salt-bridge is examined.