Ionic bond-definition-example-properties and formation condition.

Ionic Bond Definition In Chemistry

Ionic bond or electro-valent bond is one type of chemical bond which is formed by the force of electrostatic attraction between cation and anion .

Actually, ionic bond is nothing but electrostatic force of attraction between the opposite ions .

What is ionic valency ?

Most of the elements have a tendency to gain more stable electronic configuration like their nearest inert gas elements .

So, one or more electrons from outer most shell of an electro-positive atom is completely transformed to the outer most shell of the electro-negative atom, resulting in the formation of stable cation and anion .

Then, they formed a compound by the electrostatic force of attraction .

The power ofcation and anion, through which they exhibits their ability to form a compound , is called electro-valency or ionic valency.

Examples of ionic compounds

There are a large number of well known ionic compounds in the world. Few examples are , NaF , MgO , KCl , CsCl CaCl2 etc .

Condition for the formation of ionic compounds

( I )In case of ionic bond formation, one of the participating element must be electro-positive and the other should be electro-negative.

That is , the difference of electronegativity between the concern two elements must be sufficient .

( II )The number of valence electron of electro-positive element should be 1 ,2 or 3 and that of electro-negative element must be 5 , 6 or 7 respectively .

( III )The size of the electro-positive element should be small and the size of the electro-negative element should be large .

( IV )The electron affinity as well as ionization energy of the participatingelectro-positive element should be small so that cation is formed very easily.

But the electron affinity value of the concern electro-negative element must be high so that , it can gain electron to form anion easily.

( V )The extent of charge on both the cation and anion should be less so that they exhibit less tendency to regain their leaving electron.

( VI )If the amount of energy released due to formation of ionic bond is so much high , then the formation of electro-valent or ionic compound becomes more favorable.

Properties of electro-valent or ionic compounds.

( I ) Actually, there is no existence of ionic bond or ionic molecule . In ionic compounds, the ions with opposite charge form an three dimensional ionic crystal.

( II ) Since, ionic bond is nothing but electrostatic force of attraction between cation and anion , so boiling point and melting point of ionic compound is high with compare to the other compounds.

( III ) Since ions have no direction, hence ionic bond have no direction . That is, ionic valency is non directional .

( IV ) The ionic compounds are ionizable. They ionized in aqueous solution or in melting condition. So they are good conductors of electricity.

( V ) Since ionic bond have no specific direction , so ionic compounds do not exhibit isomerism properties .

(VI ) Ionic compounds are generally polar. Hence they are soluble in polar solvent like water. But they are insoluble in non-polar solvent ( CCl4 , CS2, C6H6 etc ).

( VII ) The rate of reaction among the ionic compounds are very much high .

( VIII ) The ionic compounds with equal electronic arrangement but different ion show integrated properties . For example , NaF and MgO .

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