Polarity refers to the separation of an electric charge in a molecule. Differences in electronegativity values can help indicate whether a bond between atoms is polar or non-polar. The atom with the higher electronegativity will tend to attract atoms more strongly and could lead to polarity in the bond.
A polar molecule has one end slightly positive and one end slightly negative. Water (H2O) is an example of a polar molecule.
As is seen in this diagram, the oxygen end of the molecule is slightly negative and hydrogen ends slightly positive because the molecule is non-symmetrical.
A non-polar molecule has equal distribution of charges which effectively 'cancel' each other out. Carbon Tetrachloride (CCl4) is an example of a non-polar molecule.
There is no negative or positive end in this molecule as the symmetric tetrahedral shape of the molecule allows for effective cancellation of charges. This molecule provides a good demonstration of the fact that molecules can be non-polar while still having polar bonds. The bonds between the carbon and the chlorine atoms are polar because of the separation of charges in the bonds, but the overall bond is non-polar because it is symmetrical.
Allotropy is the property of some elements to exist in two or more forms. Allotropes are the structural modifications of these elements.
Examples:
No comments:
Post a Comment