CHEMICAL BONDINGS

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"The attractive force which holds various constituents together in different chemical species is called Chemical bonding"

 Types of Chemical bonding - 

1. Ionic Bond - The bond formed as a result of electrostatic attraction between the positive(+ve) and negative(-ve) ions is called electrovalent or Ionic Bond. 
2. Covalent Bond - One or more pairs of electrons are shared by the two atoms. Langmuir introduced the term of covalent bond in 1919. 
These are two type of covalent bond is following:

• Polar Covalent Bond - 
The bonding electrons shared unequally between two atoms partial charges on atoms. 
 Example: H2O, HCl, PCl3, PCl5. (The central atom attracts molecules more strongly than surrounding atoms) 
• Non-Polar Covalent Bond - 
The bonding electrons shared equally between two atoms. No charges on atoms. 
Example: Cl2, H2, O2, N2, F2 
• Co-ordinate Bond - 
It is also known as Dative Bond. The Bond formed between two atoms in which only one atom contributes both electrons for bonding while the sharing is done by both. 
(There is no basic difference between ordinary covalent Bond and coordinate covalent Bond) 
Example: NH3, BF3. 

The difference between Ionic Compounds & Covalent Compounds

 Ionic Compounds 
• It is crystalline solid at room temperature. 
• Hard and brittle. 
• High melting & boiling points. 
• Insulator in solid state but condutor in molten phase or aquous solution. 
• Soluble in polar solvent. 
• Reactions are very fast. 
• It is non-rigid and non-directional.
Covalent Compounds
• It is solid, liquid, and gas at room temperature. 
• It is usually soft except solids. 
• Low melting & boiling points
• It is bad conductors of electricity. 
• Soluble in non-polar solvents,like CS2, CCl4, C6H6, Hydrocarbons. 
• It reacts slower than ionic compounds. 
• It is rigid and directional. 



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