Polar covalent bond

Definition

A polar covalent bond is a type of chemical bond where two atoms share electrons unequally, resulting in a molecule with a partial positive charge on one end and a partial negative charge on the other. This occurs due to differences in electronegativity between the bonded atoms.

5 Must Know Facts For Your Next Test

1. Polar covalent bonds form when there is a significant difference in electronegativity between the bonded atoms, typically ranging from 0.5 to 1.7.
2. In a polar covalent bond, the atom with higher electronegativity attracts the shared electrons more strongly and becomes partially negative (δ-), while the other atom becomes partially positive (δ+).
3. Water (H2O) is a common example of a molecule with polar covalent bonds, where oxygen is more electronegative than hydrogen.
4. Polar covalent bonds contribute to the overall polarity of molecules, which affects properties like solubility and boiling point.
5. Molecules with polar covalent bonds can engage in dipole-dipole interactions, influencing their physical and chemical behavior.

Review Questions

• What causes the unequal sharing of electrons in a polar covalent bond?
• How does electronegativity difference determine whether a bond will be polar covalent?
• Give an example of a molecule that has polar covalent bonds and explain why it is considered polar.

Related terms

Electronegativity: The ability of an atom to attract shared electrons in a chemical bond.

Dipole Moment: A measure of the separation of positive and negative charges in a molecule.

Ionic Bond: A type of chemical bond formed through the electrical force between oppositely charged ions, usually between metals and nonmetals.