From memory, electrons from the outer "shell" of a metal molecule, are free to move around in a sort of electron "sea", and are not necessarily moving between atoms. But that may be just a convenient visualisation, like electron "shells"
"For ordinary currents, this drift velocity is on the order of millimeters per second in contrast to the speeds of the electrons themselves which are on the order of a million meters per second. Even the electron speeds are themselves small compared to the speed of transmission of an electrical signal down a wire, which is on the order of the speed of light, 300 million meters per second." http://hyperphysics.phy-astr.gsu.edu/hbase/electric/ohmmic.html
