Final answer:
In a metallic bond, positive metal ions attract mobile valence electrons that move freely within the metal's structure.
Step-by-step explanation:
A metallic bond forms when positive metal ions attract mobile electrons. These electrons are not fixed in place and are able to move freely throughout the metal lattice. This structure consists of positively charged metal cations surrounded by a sea of delocalized, or mobile, valence electrons. This arrangement allows metals to conduct electricity and heat efficiently and gives them their malleability and ductility.