When electrons move from one atom to another within a metal, it is referred to as electron transfer or electron migration. This phenomenon is responsible for various properties of metals, including their electrical conductivity.
In a metal, the outermost electrons of each atom, known as valence electrons, are relatively loosely bound to their respective atomic nuclei. This means that they are not strongly localized around individual atoms but rather can move freely throughout the entire metal lattice.
When an electric field is applied to a metal or when thermal energy is present, valence electrons can gain enough energy to overcome the attractive forces from their parent atoms and move through the lattice. These mobile electrons are often referred to as "free electrons" or "conduction electrons."
As the free electrons move through the metal lattice, they are not associated with any specific atom. Instead, they form a "sea" of delocalized electrons that can move relatively unhindered. This collective movement of electrons allows metals to conduct electricity.
It's important to note that while the free electrons move throughout the metal, the positive ions (atomic nuclei) in the lattice remain in fixed positions. The lattice structure of the metal is essentially a positively charged array of ions surrounded by a cloud of free electrons.
When an external electrical potential is applied across a metal, the free electrons are influenced by the electric field and drift in a specific direction. This electron flow constitutes an electric current. The ability of metals to readily transfer electrons from one atom to another is why they are excellent conductors of electricity.
Overall, when electrons move from one atom to another in a metal, they contribute to the flow of electric charge and play a central role in the unique properties of metals, including their high electrical conductivity.