Covalent bonding is described as the sharing of electrons, but when two or more atoms share their electrons to form a bond, often times the electrons are not shared evenly. This uneven sharing of electrons creates a partial positive and partial negative end of the molecule, or we can say that molecules resulting from the uneven sharing of electrons are polar. Note: The electronegativity video introduced from last chapter is also shown below.
8.4 Bond Polarity and Electronegativity
It would be convenient to simply characterize a bond as either ionic or covalent, but in reality there is a continuum of bonding and it is fairly difficult to place black and white boundaries on the types of bonding we will observe.
8.4 Ionic vs. Covalent Bonding