What is the maximum number of electrons in the second electron shell?

• A. 2
• B. 32
• C. 8
• D. 18

Answer: (C)

Think about how electrons fill shells: each shell can hold a certain number of electrons based on the orbitals it contains. The maximum number in a shell follows 2n^2, where n is the shell number. For the second shell, n = 2, so 2n^2 = 2 × 4 = 8. This fits by counting the subshells: 2s can hold 2 electrons, and 2p has three orbitals with 2 electrons each, giving 6 more. 2 + 6 = 8. For reference, the first shell holds 2, the third shell up to 18, and the fourth up to 32. So the maximum in the second shell is 8.