How many electron pairs are shared between carbon atoms in a molecule that has the formula C₂H₄?
A) one
B) two
C) three
D) four

Question

Quizplus · Accepted Answer

Each carbon atom in C₂H₄ forms two single covalent bonds with two hydrogen atoms, and one double covalent bond with the adjacent carbon atom. Therefore, there are two electron pairs shared between the carbon atoms (forming the double bond), and one electron pair per carbon atom shared with a hydrogen atom. This adds up to a total of four electron pairs shared between the carbon atoms, but since two of them are in a double bond, we only count them once. Thus, the answer is two.

How Many Electron Pairs Are Shared Between Carbon Atoms in a Molecule