CBSE Class 10 Answered

Non-polar covalent bond:

• Non-polar covalent bond is formed between the two atoms of the same element.
• Atoms of the same element attract electrons equally.
• So, when a covalent bond is formed between two atoms of the same element; the electrons are shared equally between the two atoms.
• In other words, the shared electron-pair will lie exactly midway between the two atoms.
• This type of covalent bond is known as a non-polar covalent bond.
• Non-polar covalent bonds are formed in the molecules such as H₂, O₂ and Cl₂ etc.

 Polar covalent bond:

• Polar covalent bond is formed between two atoms of different elements; the shared pair of electrons does not lie exactly midway between the two atoms and it lies more towards the atom which is more electronegative.
• The atom with higher affinity for electrons develops a slight negative charge and atom with lesser affinity for electrons a slight positive charge.
• In the hydrogen chloride (HCl) molecule, hydrogen and chlorine atoms are bonded through electrons sharing.
• The shared pair of electrons lies more towards Cl atom (because Cl is more electronegative). Therefore, Cl atom acquires a slight negative charge (-?) and H atom, a slight positive charge (+?).