Question

Which of the following bonds has the highest energy?

• A. $\mathrm{O}-\mathrm{O}$
• B. $\mathrm{S}-\mathrm{S}$
• C. $\mathrm{Se}-\mathrm{Se}$
• D. $\mathrm{Te}-\mathrm{Te}$

Answer 1

The correct option is B

$\mathrm{S}-\mathrm{S}$

Explanation for correct option:

B. $\mathrm{S}-\mathrm{S}$

Bond energy:

• “Bond energy is a measure of the bond strength of a chemical bond.”
• It is the amount of energy required to break the atoms involved in a molecular bond into free atoms.

$\mathrm{S}-\mathrm{S}$ have the highest bond energy, which is due to lower size and less electron-electron repulsion. As on moving down the group, the size increases due to which the M-M bond becomes weaker.

Expalantion for incorrect options:

A. $\mathrm{O}-\mathrm{O}$

• The highest bond energy will be in $\mathrm{S}-\mathrm{S}$, the bond energy for $\mathrm{O}-\mathrm{O}$ is weaker than that of $\mathrm{S}-\mathrm{S}$ due to higher interionic repulsions between oxygen atoms due to its small size.

C. $\mathrm{Se}-\mathrm{Se}$

• Due to more size, the bond energy will be the least.

D. $\mathrm{Te}-\mathrm{Te}$

• The size of Tellurium is the largest among other elements present in the same group. Thus it will have the least bond energy.

Hence, the correct option is B i.e. $\mathrm{S}-\mathrm{S}$.