What is the reason behind that when Li and Cl make bond, the Li does not completes its duplet whereas Cl completes its octet by making covalent bond with Li but the compound LiCl is formed ,but here as Li is not completing its duplet then how is it getting stable? Instead of making covalent bond they can make ionic bond with which both can attain stability but it dosen't happens. WHY?

 

 Dear student

LiCl if formed by ionic bonding.

Formation of LiCl 
Li
Atomic number = 3
Electronic configuration = 1s²2s¹ 
Cl 
Atomic Number = 17
Electronic configuration = [Ne] 3s²3p⁵ 
Li loses one electron to form cation: Li → Li⁺ + e^- 
Cl gains one electron to form anion: Cl + e^- → Cl^- 
An electrostatic force of attraction takes place between Cl^- and Li⁺ 
Cl^- + Li⁺  → LiCl

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LiCl is an ionic compound but the covalent character of LiCl is quite high in comparison of metal chlorides of same group. This can be explained on the basis of fajan's rule. According to which smaller is the cation higher will be its polarizing power and higher will be its covalent character.

As size of Li ⁺ ion is very small and smaller then all other metals of same group therefore the covalent character of LiCl is very high in comparison of other .


Regards

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