What makes a molecule polar?
Polar molecules are those that possess regions of positive and negative charge. Water is an example of a polar material. The type of bonds it has, when coupled with its shape, gives one end of the molecule a slight positive charge (the hydrogen end) and the other a slight negative charge (the oxygen end).
| Difference between Polar and Nonpolar | |
|---|---|
| POLAR | NONPOLAR |
| Asymmetrical | Symmetrical |
| Has electrical poles | It does not have electrical poles |
| One end of the molecule has a positive whereas the other end has a negative charge | It does not have profusion of charges at opposite ends |
Polar molecules occur when there is an electronegativity difference between the bonded atoms. Nonpolar molecules occur when electrons are shared equal between atoms of a diatomic molecule or when polar bonds in a larger molecule cancel each other out.
The two general requirements for a polar molecule are (1) polar bonds and (2) a structure such that the bond dipoles of the polar bonds do not cancel.
The shape of a molecule and the polarity of its bonds determine the OVERALL POLARITY of that molecule. A molecule that contains polar bonds, might not have any overall polarity, depending upon its shape.
Examples of polar molecules are HCl,H2O,NH3, and that of non-polar molecules are H2,O2,Cl2.
Water (H2O), like hydrogen fluoride (HF), is a polar covalent molecule. When you look at a diagram of water (see Fig. 3-2), you can see that the two hydrogen atoms are not evenly distributed around the oxygen atom.
The typical rule is that bonds with an electronegativity difference less than 1.6 are considered polar.
what is a polar molecule? A polar molecules have a region with a slight negative charge and a slight positive charge.
The polarity of bonds is caused due to the interaction of the bonds between molecules and atoms with different electronegativities. Consider an electromotive force (EMF) or an electric potential, acting between two points. Here, the points or poles have a greater number of electrons than the other.