[عاطف خليفة]

* METALLIC BOND

1- Metallic bond is :-

1- Produced from the electron cloud of valence electrons which decrease the repulsive forces between the positive ions in the crystal lattice.

2- The strength of the bond increases as the number of valence electrons increases.

3- Free valence electrons account for good electrical and thermal conductivity

4- As the valence electrons increase the metal becomes more hard and has high melting and boiling points (comparison between Na, Mg, Al).