Key Concepts: Metallic Bonding

Metallic bonding refers to the strong attraction between closely packed positive metal ions and a ‘sea’ of delocalized electrons.
It is an example of electrostatic forces of attraction, specifically between positively charged ions and negatively charged electrons.
This bond type is found in elemental metals and alloys, creating unique properties associated with metals.
The arrangement of atoms in metallic bonding forms a regular structure, creating a lattice in which each positive metal ion is surrounded by electrons.
Delocalized electrons are free to move, giving rise to many characteristic properties of metals, such as thermal and electrical conductivity, malleability, and ductility.
The strength of a metallic bond can vary based on the number of electrons involved in bonding, as well as the charge and size of the metal ion. More electrons and smaller, highly charged ions result in stronger bonds and hence higher melting and boiling points.
In essence, every atom in metallic bonding loses its outer shell electrons, turning into a positively charged ion. Those outer shell electrons then become ‘delocalized,’ meaning they can move around freely among the ions.
Metallic bonding is responsible for the typical shiny appearance of metals, as the delocalized electrons reflect light.
Metals have high melting and boiling points due to the strength of the metallic bonds, which require a significant amount of energy to break.
Another key property derived from metallic bonding is the malleability and ductility of metals, which means they can be bent, stretched, and shaped without breaking. This is because the layers of ions can slide over each other without disrupting the metallic bonding.
Metals are generally good conductors of heat, as the increase in kinetic energy caused by heating can be easily transferred through the interaction between delocalized electrons and metal ions.
Metals also conduct electricity because the delocalized electrons can move and carry an electric charge throughout the metal lattice.
Despite being strong, metallic bonds are non-directional. This means they do not favour interaction in any specific direction, unlike covalent bonds.
The properties of metallic bonds also result in metals having high densities. The close packing of ions within the lattice, coupled with their larger atomic masses, results in a higher mass per unit volume.