Advanced Placement (AP) Chemistry Practice Exam

The type of bonding characterized by a 'sea of electrons' is metallic bonding. In metallic bonding, metal atoms collectively contribute their valence electrons to form a delocalized electron cloud that surrounds positively charged metal ions. This 'sea of electrons' allows for the electrons to move freely throughout the structure, which accounts for many of the unique properties of metals, such as electrical conductivity and malleability. The strong electrostatic attraction between these delocalized electrons and the positively charged metal ions helps to hold the metal structure together, contributing to the overall stability and characteristics of metallic substances. This phenomenon is distinct from the bonding types like polar covalent, ionic, and covalent bonding, where electron sharing or transfer occurs in more localized ways.