Question

i. How is covalent bond formed between two atoms? 

ii. Consider two covalently bonded atoms Q and R where R is more electronegative than Q. 

Will these atoms share the electron pair equally between them? 

iii. Represent the above polar covalent bond between Q and R using fractional charges δ⁺ and δ^-.

Answer 1

i. A covalent bond is formed between two atoms by mutual sharing of electrons so as to complete their octets or duplets (in case of elements having only one shell).

ii. A covalent bond is formed between Q and R having different electronegativities, that is, R is more electronegative than Q. 

In such a case,

The atom R with a higher value of electronegativity pulls the shared pair of electrons to a greater extent towards itself as compared to the atom Q with lower value of electronegativity. 

As a result of this,

The shared pair of electrons will get shifted towards atom R. 

Thus,

Both the atoms Q and R will not share the electron pair equally between them.

iii. Polar covalent bond between Q and R can be represented as :

\(Q^{δ+}-R^{δ-}\)