Bond Polarity

Using the Electronegativities we can predict whether a given bond will be non-polar, polar covalent, or ionic. The greater the difference in electronegativity the more polar the bond.

Order the following bonds according to polarity: H-H, O-H, Cl-H, S-H, and F-H.

In practice no bond is totally ionic. There will always be a small amount of electron sharing.

So what is and ionic compound? There's no clear cut line. Therefore we use the following practical definition for an ionic compound

Ionic Compound is any solid that conducts an electric current when melted or dissolved in water.

Or you can simply say that a "salt" is an ionic compound.

Once again, the picture we're forming is that, in virtually every case, the atom in a stable compound has a noble gas arrangment of electrons. When two non-metals react to form a covalent bond, they share electrons in a way that completes the valence electron configurations of both atoms (i.e., both non-metals attain a noble gas configuration).