Answer :
Many of the unique properties of metals can be explained by metallic bonds.Metallic bonds can occur between different elements to form an alloy.In contrast to electrons that participate in both ionic and covalent bonds, electrons that participate in metallic bonds delocalize, forming a sea of electrons around the positive nuclei of metals. The availability of "free" electrons contributes to metals being excellent conductors.
Electron sea model: Electrons all have approximately the same energy.
Band theory: Electrons move among orbitals of different energies.
Both models: Electrons move freely among atoms (delocalized).