Positive ions in a sea of electrons are found in

Step 1: Analyze the question The question describes a structure with "positive ions in a sea of electrons." We need to identify which type of bonding matches this description.

Step 2: Explain the concept Each type of bond has its own features:

• Covalent bond: atoms share pairs of electrons (e.g., H₂, CH₄).
• Metallic bond: metal atoms lose their valence electrons, which become delocalised. The result is a lattice of positive metal ions surrounded by a "sea" of free-moving electrons. The electrostatic attraction between the ions and the electrons holds the metal together.
• Dative (coordinate) bond: both electrons in the shared pair come from one atom (e.g., NH₄⁺, H₃O⁺).
• Ionic bond: electrons are transferred from a metal to a non-metal, forming oppositely charged ions held together by electrostatic attraction (e.g., NaCl). There is no "sea of electrons."

Step 3: Apply to the question The phrase "positive ions in a sea of electrons" is the classic description of metallic bonding. It also explains why metals conduct electricity (the free electrons move), and why they are malleable and ductile (layers of ions can slide without breaking the bonding).

Step 4: Answer The correct option is B. metallic bonds.

Tip: Link the key words to the bond type:

• "Sea of electrons" or "delocalised electrons" → metallic
• "Sharing" → covalent
• "Transfer" → ionic
• "One atom donates both electrons" → dative