Chemical Bonds

Chemical bonds are unions between atoms forming a stable system or association. There are two types of bounds.
 * 1) Primary Bonds: in these unions the electrons are shared or transferred to other atoms. In this classification are the Ionic, Covalent and Metalic bonds.
 * 2) Secondary Bonds: in these unions there are not any transferred electrons, atoms are attracted by forces. Ex: Van Der Waals forces.

Ionic Bond
These bonds are formed in atoms with a big difference in their electro-negativities (1.7 approximately), that is to say, one of them tends to attract electrons and the others tend to lose their electrons. The electrons are transferred from one to the other

Characteristics:


 * Crystaline in normal temperatures.
 * Elevated fusion and boiling points.
 * Highly hardness.
 * Fragile.
 * They resist the dilatation.
 * Soluble in polar compounds.
 * Insulating.

Covalent Bonds
In covalent bounds the atoms share their own electrons to form an stable system. The electro-negativities usually are high and approximate (no metal with no metal).

Metal Bonds
In metal compounds the electrons are distributed along the material with non-directional structure. The atoms have a low and approximate electro-negative value (metals). The compounds usally lose their electrons.



They do not have much valency electrons in their structure, these electrons are dislocated so it is difficult to them to be associ

ated with an specific atom. The dislocation forms an electronic cloud which produces a high electrical and termical conductivity.

They have the same charasteristics as metals.

Van der Waals Forces


They are attraction forces between atoms similar like ionic bonds, but in this case it is not any electron sharing.