Answer:
The light blue area in a diagram of metallic bonding represents a sea of delocalized electrons.
Step-by-step explanation:
In metallic bonding, metal atoms are held together by a lattice of positively charged metal ions surrounded by a sea of delocalized electrons. These electrons are not associated with any particular atom and are free to move throughout the lattice, giving metals their characteristic properties such as electrical conductivity and malleability. The delocalized electrons are represented by the light blue area in the diagram, which surrounds the metal ions.