Which of the following elements can have expanded octets in their compounds?

• A. C (carbon)
• B. P (phosphorus)
• C. N (nitrogen)
• D. O (oxygen)

Answer: (B)

Verified step by step guidance

1. Understand the concept of an expanded octet: Elements that can have expanded octets are those that can accommodate more than 8 electrons in their valence shell, typically because they have available d orbitals starting from the third period of the periodic table.
2. Identify the period of each element: Carbon (C) is in period 2, Nitrogen (N) is in period 2, Oxygen (O) is in period 2, and Phosphorus (P) is in period 3.
3. Recall that elements in period 2 cannot have expanded octets because they lack d orbitals and are limited to 8 electrons in their valence shell.
4. Recognize that Phosphorus, being in period 3, has access to 3d orbitals, allowing it to hold more than 8 electrons and thus form compounds with expanded octets.
5. Conclude that among the given elements, only Phosphorus (P) can have expanded octets in its compounds.