How many electrons can occupy the 4p subshell, and what are the possible ml values for these orbitals?

• A. 6 electrons; ml = -1, 0, +1
• B. 4 electrons; ml = -2, -1, 0, +1
• C. 8 electrons; ml = -2, -1, 0, +1, +2
• D. 2 electrons; ml = 0

Answer: (A)

In a p subshell (l = 1) there are 2l + 1 = 3 orbitals, with magnetic quantum numbers ml = -1, 0, +1. Each orbital can hold 2 electrons with opposite spins, so a p subshell can accommodate 3 × 2 = 6 electrons. The principal quantum number n only shifts the energy level; it doesn’t change the number of orbitals in the p subshell. Therefore, the 4p subshell can hold up to 6 electrons, and the possible ml values for these orbitals are -1, 0, and +1.