Which of the following d shell electron configurations is most likely to exhibit strong paramagnetism?

• A. d^5
• B. d^8
• C. d^10
• D. d^0

Answer: (A)

Verified step by step guidance

1. Recall that paramagnetism arises from the presence of unpaired electrons in an atom or ion. The more unpaired electrons, the stronger the paramagnetism.
2. Understand that the d subshell can hold up to 10 electrons, and the electron configurations range from d^0 (no electrons) to d^{10} (fully filled).
3. Apply Hund's rule, which states that electrons fill degenerate orbitals singly first, maximizing the number of unpaired electrons before pairing up.
4. Analyze each configuration: d^0 has no electrons (no paramagnetism), d^{10} has all electrons paired (no paramagnetism), d^8 has some paired and some unpaired electrons, and d^5 has exactly one electron in each of the five d orbitals, all unpaired.
5. Conclude that the d^5 configuration has the maximum number of unpaired electrons, making it the most likely to exhibit strong paramagnetism.