Which of the following bonds has the highest bond energy ?

Options

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

Answer

To determine which bond has the highest bond energy among the given options (sulfur-sulfur, oxygen-oxygen, selenium-selenium, and tellurium-tellurium), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Bond Energy and Bond Length Relationship**:
- Bond energy is the amount of energy required to break a bond between two atoms. It is inversely proportional to bond length; that is, shorter bonds generally have higher bond energies.

2. **Identify the Elements**:
- The elements in question belong to the oxygen family (Group 16 of the periodic table): oxygen (O), sulfur (S), selenium (Se), and tellurium (Te).

3. **Consider the Trend in Atomic Size**:
- As we move down the group from oxygen to tellurium, the atomic size increases due to the addition of electron shells. This results in an increase in bond length.

4. **Analyze the Expected Bond Energy Order**:
- Based on the trend of increasing atomic size, we would expect the bond energy to decrease as we go from oxygen to tellurium:
- Expected order: O-O > S-S > Se-Se > Te-Te.

5. **Account for Inter-electronic Repulsions**:
- However, the bond length of the O-O bond is affected by inter-electronic repulsions between the lone pairs of electrons on the oxygen atoms. This repulsion causes the O-O bond to be longer than expected.

6. **Determine Actual Bond Energy Order**:
- Due to the increased bond length of the O-O bond caused by these repulsions, the actual order of bond energies is:
- S-S > O-O > Se-Se > Te-Te.
- Thus, sulfur-sulfur (S-S) bond has the highest bond energy among the given options.

7. **Conclusion**:
- Therefore, the bond with the highest bond energy is the sulfur-sulfur bond (S-S).

### Final Answer:
The bond with the highest bond energy is the **sulfur-sulfur (S-S) bond**.

---