Tag: bonding in metals

Electron Pool Theory. 

Metallic bonding arises from the electrostatic attractive force between conduction electrons (in the form of an electron cloud of delocalized electrons) and positively charged metal ions. It may be described as the sharing of free electrons among a lattice of positively charged ions (cations). 

Metallic bonding may be described as the sharing of free electrons among a lattice of positively charged metal ions. The structure of metallic bonds is very different from that of covalent and ionic bonds. While ionic bonds join metals to nonmetals, and covalent bonds join nonmetals to nonmetals, metallic bonds are responsible for the bonding between metal atoms. In metallic bonds, the valence electrons from the s and p orbitals of the interacting metal atoms delocalize. That is to say, instead of orbiting their respective metal atoms, they form a sea of electrons that surrounds the positively charged atomic nuclei of the interacting metal ions. The electrons then move freely throughout the space between the atomic nuclei.

In a metallic bond, electrons are shared with more than one atoms. Due to this, the valance electrons are spread all over the crystal. Hence, metallic bonds are non-directional.

Metallic bonding is the strong attraction between closely packed positive metal ions and a 'sea' of delocalised electrons. So,high energy is required to overcome this bond, hence high temperature can be used to weaken or overcome these attractive forces.

(A) : The model of metallic bonding where electrons float free in a sea of electrons around metal atoms.
This model proposes that all the metal atoms in a metallic solid contribute their valence electrons to form a "sea" of electron. The electrons present in the outer energy levels of the bonding metallic atoms are not held by any specific and can move easily from one atom to the next.

The electrons can move freely within molecular orbitals, and so each electron becomes detached from its parent atom. The electrons are said to be delocalised. The metal is held together by the strong forces of attraction between the positive nuclei and the delocalised electrons.This is sometimes described as "an array of positive ions in a sea of electrons".