Which species should have the shortest bond length?

A.) N2

B.) O2

C.) SO2

D.) SO3

The correct option is: A) N₂

Explanation:

The Bond length of a chemical bond is the length of a chemical bond formed between two given atoms.

Bond length is inversely proportional to the bond order of the chemical bond, which is the total number of bonds between two atoms. Thus as the bond order increases, the bond length decreases.

A) N₂: The nitrogen-nitrogen bond in dinitrogen is a triple bond (N≡N).

Thus the bond order = 3.

B) O₂: The oxygen-oxygen bond in dioxygen is a triple bond (O=O).

Thus the bond order = 2.

C) SO₂: Sulfur dioxide is a resonance stabilized molecule and its resonance hybrid shows that the sulfur-oxygen bond in sulfur dioxide is a partial double bond.

Thus the bond order = 1.5

D) SO₃: Sulfur trioxide is a resonance stabilized molecule and its resonance hybrid shows that the sulfur-oxygen bond in sulfur trioxide is a partial double bond.

Thus the bond order = 1.33

Since the bond order of N₂ is the largest, therefore, the N-N bond length is the shortest.