8 posts • Page 1 of 1
I believe to determine if a molecule is polar or non-polar, it is only important to know the charges on the ends of the molecule and the difference in electronegativity between bonded atoms, since ionic bonds are pretty much guaranteed to be polar.
If the molecule is not symmetric, then it is (generally) polar because the dipole moments (if any) do not cancel out. If the molecule is symmetric but the outside atoms are not the same, then it is polar because the dipole moments do not cancel out. If the molecule is symmetric and the outside atoms are the same, then it is non-polar.
In order to determine if the bond itself is polar, we look at the difference in electronegativity of the elements involved along with the characteristics of these elements (does it dissolve in water, etc.). If asked if the entire molecule is polar or nonpolar, that is when we look at if the molecule is symmetrical and if the outside atoms are the same/different.
Only diatomic molecules (ex. H2) have a truly nonpolar bond. If the two elements involved in the bond are different, there's going to be at least a little bit of electronegative difference, which results in a slightly polar covalent bond. Polarity of an entire molecule is different than when we are talking about the polarity of a single bond between two of the elements.
Who is online
Users browsing this forum: No registered users and 1 guest