Here's why:

* Metallic bonding is a type of chemical bonding that occurs between metal atoms.

* In metallic bonding, the valence electrons of the metal atoms are delocalized, meaning they are not associated with any particular atom but rather move freely throughout the entire metal lattice.

* This delocalization of electrons results in a strong attraction between the positively charged metal ions and the negatively charged electron "sea," holding the metal atoms together in a strong and rigid structure.

Cobalt is a transition metal, and like other transition metals, it exhibits metallic bonding. This is why cobalt is a good conductor of electricity and heat, has a high melting point, and is malleable and ductile.