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Introduciton to Metallic Bonding

In simple terms metallic bonding is referred to as bonding in metal atoms. It is also defined as interaction between metal nuclei and the delocalized electrons. Delocalized electrons are also called as conduction electrons. Metals nuclei are the positive ions and so Metallic bonding can be imagined as Sea of electrons in which positive metal ions are embedded. Positive metal ions are called as Kernels. Thus metallic bonding can be summarized as: - The force of attraction which binds together the positive metal ions or Kernels with the electrons within its sphere of influence.


Diagrammatic Representation of Metallic Bonding: -


 metallic bond


Metallic Bond Examples: - Zn -------->  Zn2+  +  2e-

These electrons are the delocalized or conduction electrons and Zn2+ are the metal ions.

The geometrical arrangements of metallic bonding can be as follows: - Face centered cubic (fcc), Hexagonal close packed (hcp), or Body centered cubic (bcc). These bonds are weaker than covalent bonds because the electrons are delocalized and mobile, therefore do not experience very strong force of attraction towards the nuclei.


Properties of Metals due to Metallic Bonding: -


1) Metals conduct heat and electricity due to mobile electrons. These act as charge and energy carriers.

2) Metals have high melting and boiling points and the values depend on the strength of the metallic bond which in turn depends on: - packing of metals ions and electrons, and also on the number of delocalized electrons.

3) Metals become malleable and ductile because the delocalized electrons can spread over thus metals can be beaten into sheets and stretched like wires.

4) Metals are lustrous because photons of light are not able to penetrate more and are reflected back quickly.

5) Metallic bonding makes the metal flexible.

Thus metallic bonding effects most of the physical properties of metals and chemically metals becomes electron donors so are highly electro positive forming cations and giving electrons for the reaction to occur. Thus they act as Reducing agents and Lewis bases.