Which statement correctly describes the maximum electrons for subshells in order S, P, D, F?

• A. 2, 6, 10, 14
• B. 2, 8, 18, 32
• C. 1, 3, 5, 7
• D. 4, 8, 12, 16

Answer: (A)

When thinking about how many electrons a subshell can hold, focus on two facts: how many orbitals the subshell has and how many electrons each orbital can contain. An s subshell has 1 orbital, so it can hold 2 electrons. A p subshell has 3 orbitals, so it can hold 3 × 2 = 6 electrons. A d subshell has 5 orbitals, so it can hold 5 × 2 = 10 electrons. An f subshell has 7 orbitals, so it can hold 7 × 2 = 14 electrons. This gives the sequence 2, 6, 10, 14 for S, P, D, F. The other sequences don’t fit because they either reflect total electrons in entire shells (2n^2) or include odd numbers, whereas each orbital can only hold two electrons.