Question

Which one of the following has the highest bond energy?

• A. $O-O$
• B. $S-S$
• C. $Se-Se$
• D. $Te-Te$

Answer 1

The correct option is B $S-S$

As we move down the group atomic size increases. As a result bond length increases and bond dissociation energy should decrease down the group but actually bond dissociation energy follows the order,
$S-S>Se-Se>O-O>Te-Te$

$S-S$ bond is the stronger covalent bond than $O-O$ as there are more lone pair- lone pair repulsions in $O-O$ due to small size of $O$ which makes the bond weak.