how can you tell if a molecule is polar? also, what is the difference between dipole and dipole-dipole molecules?

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sanjeetmanna | College Teacher | (Level 3) Assistant Educator

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A polar molecule which has a net dipole moment due to its having unsymmetrical polar bonds.

There are two factors that go into determining if a molecule is polar or non polar

  • The polarity of the individual bonds in the molecule.

  • The shape or geometry of the molecule.


Greater the electronegativity difference, the more ionic the bond is. Bonds that are partly ionic are called polar covalent bonds.

A bond between 2 nonmetal atoms with different electronegativities and have unequal sharing of the bonding electron pair

Example: HCl

The bond where the electron pair is displaced toward the more electronegative atom obtains a partial-negative charge while the less electronegative atom has a partial-positive charge


Dipole molecules in which different atoms are bonded by a covalent bond, which can have different electron affinity, then the the atom with greater electron affinity will attract the electron pairs more strongly.

Dipole-dipole molecule have Dipole-dipole force which are attractive forces between the positive end of one polar molecule and the negative end of another polar molecule.

Dipole-Dipole forces are the attractive forces between molecules that have a permanent net polarity. That is, between polar molecules.