Polar molecule

Definition

A polar molecule has a net dipole moment due to the uneven distribution of electrons between atoms with different electronegativities. This results in one end of the molecule having a partial positive charge and the other end having a partial negative charge.

5 Must Know Facts For Your Next Test

1. Polar molecules interact strongly with electric fields, aligning themselves with the field direction.
2. Water (H2O) is a common example of a polar molecule, important for understanding biological electric forces.
3. The dipole moment ($\mu$) of a polar molecule is given by $\mu = q \times d$, where $q$ is the magnitude of charge and $d$ is the separation distance.
4. Polar molecules affect the capacitance of capacitors when used as dielectrics by increasing the capacitance value.
5. In an electric field, polar molecules experience torque that tends to align them with the field.

Review Questions

• What causes a molecule to become polar?
• How do polar molecules behave in an external electric field?
• Why are polar molecules significant in biological systems?

Related terms

Dipole Moment:

A measure of the separation of positive and negative charges in a system; mathematically represented as $\mu = q \times d$.

Dielectric:

An insulating material that can be polarized by an electric field, affecting its behavior in capacitors.

Electronegativity:

The tendency of an atom to attract electrons towards itself within a chemical bond.