Polar covalent bonds

Polar covalent bonds

A polar covalent bond is a type of chemical bond formed between atoms of different elements, where the shared pair of electrons is not shared equally due to differences in electronegativity.

Definition:

• In a polar covalent bond, the shared pair of electrons is not equally shared between the two atoms.
• This occurs because one of the atoms involved in the bond has a higher electronegativity, which means it has a stronger attraction for the electrons.

Key Characteristics:

• Polar covalent bonds typically form when there is a significant difference in electronegativity between the two atoms.
• The atom with the higher electronegativity will attract the shared electrons more strongly, resulting in a partial negative charge (δ⁻) on that atom and a partial positive charge (δ⁺) on the other atom.
• The separation of charges creates a dipole moment, represented by an arrow pointing from the δ⁺ to δ⁻.

Example:

Hydrogen Bromide (HBr):

• In the molecule HBr, hydrogen (H) and bromine (Br) have different electronegativities.
• Bromine, being more electronegative, attracts the shared electrons more strongly.
• This leads to a partial negative charge (δ⁻) on the bromine atom and a partial positive charge (δ⁺) on the hydrogen atom.
• The bond in HBr is polar covalent, and there is a dipole moment with an arrow pointing from hydrogen to bromine.

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Polar covalent bonds

Significance:

• Polar covalent bonds are common in many compounds and play a crucial role in determining the overall polarity of molecules.
• Understanding polar covalent bonds helps explain the unequal sharing of electrons in various substances, affecting their chemical properties and interactions.