Discus of metallic Bond

Metallic Bond

A less mentioned type of bonding is the metallic bond. In this type of bonding, all metallic atoms lodes their valence electron from a pool of electrons, which is mobile. Leaving the valence electrons, the remainder portion of the metal atom is a positive ion called “kernel”.

For example, in lithium each atom contributes are valence electron to the pool leaving behind Li⁺ ions; in case of Mg, each atom contributes two valence electron to the pool leaving behind Mg²⁺ ions. These positive ions or kernels are held in the three dimensional space in a definite pattern in the sea of mobile electrons. This model is called electron gas model because the electrons are free to move in all direction like the molecules of a gas.

   Structure of metals (electron sea model)

The simultaneous attraction between the kernels and the mobile electrons which holds the kernels together is called metallic bond. Metallic bonding may be seen as an extreme example of delocalization of electrons over a large system of covalent bonds, in which every atom participates. This type of bonding is often very strong resulting in the tensile strength of metals. However, metallic bonds are more collective in nature than other types, and so they allow metal crystals to deform more easily, because they are composed of atom attracted to each other, but not in any particularly-oriented ways. This results in the malleability of metals. The sea of electrons in metallic bonds causes the characteristically good electrical and thermal conductivity of metals, and also their “shiny” reflection of most frequencies of white light.

All types of chemical bonds can be explained by quantum theory, but, in practice, simplification rules allow chemists to predict the strength, irrationality, and polarity of bonds. The octet rule and VSEPR theory are two examples, More sophisticated theories are valence theory which includes orbital weatherization and resonance, and the linear combination  of atomic orbitals which is the basis for the extraordinary molecular orbital method.