Which representation depicts covalent bonds and shows no bonding valence electrons?

• A. Lewis Structure
• B. Resonance Structure
• C. Lewis dot structure
• D. Bond-line diagram

Answer: (A)

Think about how covalent bonds and valence electrons are shown in common diagrams. In a Lewis structure, covalent bonds are represented by shared electron pairs between atoms, usually drawn as a line (or sometimes as a pair of dots) between the atoms. The key is that the bonding electrons aren’t drawn as separate electrons around each atom; the bond line itself signifies the two electrons being shared. You can still place lone-pair electrons around atoms with dots, but the bonding electrons are represented by the connection between atoms rather than as individual dots on each atom.

That makes the Lewis structure the best choice for depicting covalent bonds while not showing bonding valence electrons as separate entities around the atoms. Resonance structures illustrate different valid ways of placing electrons in molecules with delocalized bonding and aren’t a single definitive depiction. Lewis dot structures are essentially the same idea but use dots for all valence electrons, including those involved in bonds. Bond-line diagrams show connectivity with lines and often omit lone pairs, which is a more skeletal form and can change what’s emphasized.