The pair of bonding electrons is unequally shared, leading to a bond having a slightly positive end and a slightly negative end. What type of bonding is described?

• A. Ionic Bonding
• B. Nonpolar Covalent Bonding
• C. Polar Covalent Bonding
• D. Metallic Bonding

Answer: (C)

Unequal sharing of electrons happens when the two atoms in a bond have different electronegativities. The more electronegative atom pulls the shared electrons closer, giving it a partial negative charge, while the other atom gets a partial positive charge. This creates a bond that is covalent (electrons are shared) but with polarity, so you have a slightly positive end and a slightly negative end. That’s what polar covalent bonding describes. If there were a large difference in electronegativity and electrons were transferred, it would be ionic bonding; if the electrons were shared equally, it would be nonpolar covalent bonding. Metallic bonding is a different scenario altogether, with a "sea" of electrons delocalized around a lattice of metal ions.