I don't quite understand this part in the explanation below "molecular dipole are only a fraction of the size of the charges on an ion" How Polar Bonds create Inter-molecular Forces: The charges on...

I don't quite understand this part in the explanation below "molecular dipole are only a fraction of the size of the charges on an ion"

How Polar Bonds create Inter-molecular Forces:

The charges on each end of a molecular dipole are only a fraction of the size of the charges on an ion, but they do cause electrical forces to occure between nearby molecules.

 

Can you please give an easier explanation?

Asked on by mattlimey

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ncchemist | eNotes Employee

Posted on

Think of this in terms of magnitude or size.  A true ion is something like the sodium cation (Na+) or the chloride anion (Cl-).  There is a full charge on the ion that is a whole integer value (1, 2, 3, etc.).  A molecular dipole is not a full charge on an atom like you find in an ion.  A dipole is a partial charge.  If two atoms covalently bonded together experience a dipole, that means that one of the atoms will have a partial positive charge and the other atom will have a partial negative charge.  This is because the electron density in the bond is shifted toward the the more electronegative atom.  But the important point here is that a dipole is merely a partial charge, whereas an ion is a full charge.  This is why they use the phrase "molecular dipole are only a fraction of the size of the charges on an ion."

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