POLAR MOLECULE Meaning and
Definition
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A polar molecule is a chemical entity that possesses a distinct non-uniform charge distribution due to an uneven arrangement of its atoms. In this context, "polar" refers to the dipole nature of the molecule. This characteristic arises when there is an electronegative atom, such as oxygen or nitrogen, involved in the molecular structure.
The polarity of a molecule is determined by the difference in electronegativity between its constituent atoms. Electronegativity represents the ability of an atom to attract electrons towards itself in a chemical bond. When atoms with different electronegativities bond, a partial positive charge (δ+) and a partial negative charge (δ-) develop among the atoms generating a dipole, which makes the molecule polar.
Polar molecules possess several defining features. Firstly, there is an asymmetry in the molecular shape, leading to an uneven charge distribution. Secondly, these molecules often exhibit strong intermolecular forces, such as dipole-dipole interactions or hydrogen bonding. Polar molecules also tend to have higher boiling and melting points due to the stronger forces of attraction between their polar components.
An archetypal example of a polar molecule is water (H2O). Its bent molecular geometry and the significant difference in electronegativity between oxygen and hydrogen result in a polar bond. Oxygen, being more electronegative, attracts the shared electrons closer to itself, creating a partial negative charge around its atom and partial positive charges around the hydrogen atoms. Overall, a polar molecule's net dipole moment is non-zero, making it hydrophilic and capable of interacting with other polar substances.
Etymology of POLAR MOLECULE
The word "polar" in the term "polar molecule" comes from the Latin word "polaris", meaning "pertaining to the pole" or "of a pivot". It is derived from the Greek word "polos", which means "axis" or "pole".
In the context of molecules, "polar" refers to the electrical polarity or charge distribution within a molecule. A polar molecule has a partially positive and partially negative charge due to an uneven distribution of electrons resulting from differences in electronegativity between its atoms. This polarity creates a separation of charges, similar to the opposite poles of a magnet, giving rise to unique properties and behavior.
