What is necessary for a metallic bonds to form

Metallic bonds can occur between different elements to form alloy. In contrast to electrons that participate in both ionic and covalent bonds electrons are that participate in metallic bonds delocalize forming a sea of electrons around the positive nuclei of metals.

The electrons must be attracted to each other.

Explanation:

The complete question is:

"What is necessary for a metallic bond to form?

The atoms should be in close proximity.

The atoms should be far apart.

The electrons must be attracted to each other.

The nuclei must contain neutrons."

The metallic bond is a force that is responsible for holding the atoms together in a metallic substance. In other words, the metallic bond occurs between two metal atoms. Metal atoms need to give up electrons to achieve the configuration of a noble gas. In this way, this type of bonding all the enveloped atoms lose electrons from their outermost layers, which move more or less freely between them, forming an electronic cloud (also known as the sea of electrons).

In other words, a metal is a set of metal cations immersed in a sea of delocalized electrons where the electrostatic attraction between positive (of the cation) and negative (of the electron) charges holds together all the atoms of the metal that forms the bond.

The metallic bond is the only bond where the electrons are not located exclusively between a pair of atoms, but are relocated among millions of them in a kind of glue or "sea of electrons" that keep them tightly bound or cohesive.

The answer is: The electrons must be attracted to each other.