Question

Which of the following molecules has an expanded octet?

• A. BCl\(_3\)
• B. NO\(_2\)
• C. NO
• D. SF\(_6\)
• E. BeH\(_2\)

Hint:

Elements in the third period or higher, like sulfur, can have an expanded octet as they have access to d-orbitals in their valence shell.

Answer 1

The Correct Option is D

An expanded octet occurs when elements from the third period and beyond can accommodate more than 8 electrons in their valence shell due to the availability of d-orbitals.
- BCl\(_3\): Boron (B) in BCl\(_3\) does not have an expanded octet. It follows the octet rule and has only 6 electrons in its valence shell.
- NO\(_2\) : NO\(_2\) does not have an expanded octet, as nitrogen follows the octet rule and has 8 electrons in its valence shell.
- NO: NO does not have an expanded octet either. Nitrogen in this molecule follows the octet rule.
- SF\(_6\) : SF\(_6\) (sulfur hexafluoride) is the correct answer. Sulfur can accommodate more than 8 electrons in its valence shell due to the availability of d-orbitals, and it forms an expanded octet in SF\(_6\).
- BeH\(_2\): BeH\(_2\) does not have an expanded octet. Beryllium (Be) follows the duet rule and only has 4 electrons in its valence shell.
Thus, the correct answer is (D) , SF\(_6\) as sulfur in this molecule has an expanded octet.