What is the maximum number of unpaired electrons possible in a d subshell (l = 2)?

What is the maximum number of unpaired electrons possible in a d subshell (l = 2)?

• A. 4
• B. 3
• C. 5
• D. 6

Answer: (C)

In a d subshell there are five orbitals. Each orbital can hold two electrons, but to maximize unpaired electrons we place one electron in each of the five orbitals with the same spin before any pairing occurs (Hund’s rule). Since there are five orbitals, the maximum number of unpaired electrons is five. This is the highest possible before any pairing must occur, so the correct result is five.

In a d subshell there are five orbitals. Each orbital can hold two electrons, but to maximize unpaired electrons we place one electron in each of the five orbitals with the same spin before any pairing occurs (Hund’s rule). Since there are five orbitals, the maximum number of unpaired electrons is five. This is the highest possible before any pairing must occur, so the correct result is five.