What type of bond allows for free movement of valence electrons among metal atoms?

A metallic bond is characterized by the sharing of free-moving valence electrons among a lattice of metal atoms. This bonding occurs when metal atoms come together, and their outermost electrons become delocalized, allowing them to move freely throughout the entire metallic structure. This movement of electrons is often described as a "sea of electrons," which contributes to several key properties of metals, such as electrical conductivity, malleability, and ductility.

In contrast, covalent bonds involve the sharing of electron pairs between specific atoms, leading to the formation of distinct and localized bonds. Ionic bonds are formed through the transfer of electrons from one atom to another, creating charged ions that are held together by electrostatic forces, which do not facilitate the free movement of electrons as seen in metallic bonds. Polar bonds, a type of covalent bond, result from unequal sharing of electrons, further restricting electron mobility when compared to metallic bonding. Thus, the nature of metallic bonding directly supports the free movement of electrons among metal atoms.