How can you tell what kind of primary atomic bonding is present by noting where the involved elements are located on the periodic table? Describe how the electronegativity difference between atoms affects the ionic/covalent character of a bond. Why do some covalently-bonded molecules have low boiling points and others have high boiling points? Solution 1. When there is Ionic bonding When there is Covalent bonding When there is Metallic bonding 2. When there is Ionic Bonding: When there is Covalent Bonding: 3. Covalent bonds can be strong because of the sharing of electrons. The secondary bonding that occurs between chains on polymers is weak which breaks down when heated. .