Why for the formation of a covalent bond both the atoms should have high electronegativity? Why should the electronegativity difference between b/w the combining atoms involved in covalent bond should be little or negligible because if the electronegativity difference between the combining atoms is high then too polar covalent compounds are formed?please give appropriate reason and explain in an easy language.
Asked by 21janhvi.verma | 6th Jun, 2018, 10:34: AM
After observing your questions it is clear that your idea about electronegativity and chemical bonding is not cleared.
Lets first understand it.
Electronegativity: It is the property of an atom of an element to attract or pull electrons towards itself.
Now, let's apply this concept to chemical bonding.
Always remember two points:
1) If the electronegativity difference between combining atoms is zero or negligible then it will form a covalent compound
2) If the electronegativity difference between combining atoms is high then it will form an ionic bond.
There is a case in covalent compounds,i.e., Polar covalent compounds
let's understand when a covalent compound is polar,
This happens when bonded atoms are dissimilar atoms with little difference in their electronegativity.
For example HCl ( electronegativity of H=2.2 and Cl = 3.16)
The difference in their electronegativity is 3.1-2.2 = 0.9 which is more than 0, hence the nature of bond will be polar
Since Cl is more electronegative than hydrogen it will attract the shared pair of electrons towards itself, thereby developing a slight negative charge (δ−) on Cl and (δ+) charge
But when HCl is in its gaseous form it will never dissociate, but when we dissolved it into a polar solvent it dissociates to form ions.
This happens because the OH- ion from water molecule will attract the H+ ion of HCl hence as both are oppositely charged they attract towards each other and bond between H-Cl is broken and dissociates to form ions.
Points to remember:
* Covalent compounds do not form ions
* Polar covalent compounds do not form ions unless they come in contact with or dissolved in the polar solvent.
* Ionic compounds are more stable than covalent compounds.
* Ionic compounds are in ionic form in their crystals but when they are in contact with or dissolved in the polar solvent they dissociate into ions.
Answered by Ramandeep | 6th Jun, 2018, 02:13: PM
- covalent bond is formed between
- number of molecules occupied by 32 gram of sulphur dioxide
- Draw the electron dot diagram and structure of: a) Hydrogen b) Chlorine c) Oxygen d) Nitrogen
- why covalent bond needs high electronagetivity
- Is atomicity of all metals is only 1?
- If the power of IP is not equal to the power of EA , will the atoms will react with each other ?
- Does ionisation occur only in polar covalent molecules or in both polar and non- polar covalent molecules?
- Draw the dot diagram for polar covalent molecule, hydrogen chloride.
- Why covalent compounds are inslouble in water?
Kindly Sign up for a personalised experience
- Ask Study Doubts
- Sample Papers
- Past Year Papers
- Textbook Solutions
Verify mobile number
Enter the OTP sent to your number