Electronegativity and Polarity

Electronegativity

-Electronegativity Table

 

- Electronegativity is a measure of the attraction of an atom for electrons in a covalent bond.

- Fluorine, the most reactive non-metal, is assigned the highest value since it has the greatest attraction for the electron being shared by the other element. Oxygen is also highly electronegative and has a strong attraction for electrons.
- Metals have low electronegativities since they have weak attraction for any shared electrons.
- When two unlike atoms are convalently bonded, the shared electrons will be more strongly attracted to the atom of greater electronegativity. Such a bond is said to be polar. A polar bond results in the unequal sharing of the electrons in the bond.

Polarity

- Polarity is a physical property of compounds which relates other physical properties such as melting and boiling points, solubility, and inter molecular interactions between molecules.

- For the most part, there is a direct correlation between the polarity of a molecule and number and types of polar or non-polar covalent bonds which are present.

- In a few cases, a molecule may have polar bonds, but in a symmetrical arrangement which then gives rise to a non-polar molecule such as carbon dioxide.