Ionic Bond

Introduction:

Every element wants to achieve noble gas configuration. Hydrogen wants to be like Helium. Sodium likes to be like Argon. To achieve this atoms have to either gain electrons or lose them or share them.

Defintion:

When an atom having excess of electrons give them to an atom in need of electrons,  they form oppositely  charged ions. The bond which holds these oppositely charged ions together is known as Ionic bond or Electrovalent bond.

Explanation:

This bond is usually formed between metals and non-metals. The positively charged ion is called Cation and negatively charged ion is called as Anion. Ionic bond is best illustrated by an example:

Sodium Chloride (NaCl): Sodium has 1 extra electron and chlrorine needs 1 electron to achieve stable configuration (Noble Gas configuration). When one atom of Sodium collides with one atom of Chlorine, the extra electron of Sodium gets transferred to the Chlrine atom. Now Sodium has one less electron so it becomes positively charged ion (Na +). Chlorine on the other hand has gained one electron so it becomes negatively charged ion (Cl -).We know that opposite charges attract each other. That is why positively charged sodium ions and negatively charged chlorine atoms attract each other to form a shape in which there is maximum attraction. In this shape each Sodium is surrounded by 6 Chlorine atoms. 

Structure of Sodium Chloride

 This is why we never refer to ionic compounds as just one "molecule". Because in reality they are several ions of opposite charges arranged in a certain shape.

Properties: 

• This type of bond is very tight.
• Ionic compounds are hard and brittle.
• They have high melting and boiling points.
• They are crystalline usually.
• When dissolved in water, they dissociate into ions again.
• They conduct electricity in molten state and when dissolved in water.