What is the maximum number of electrons that can occupy the third energy level (n = 3) in an atom?

• A. 6
• B. 18
• C. 8
• D. 32

Answer: (B)

Verified step by step guidance

1. Recall that the maximum number of electrons in a given energy level (principal quantum number \( n \)) is determined by the number of orbitals available in that level and the fact that each orbital can hold up to 2 electrons.
2. The number of orbitals in an energy level is given by \( n^2 \). For \( n = 3 \), calculate the number of orbitals as \( 3^2 = 9 \).
3. Since each orbital can hold 2 electrons, multiply the number of orbitals by 2 to find the maximum number of electrons: \( 9 \times 2 \).
4. Therefore, the maximum number of electrons in the third energy level is \( 2n^2 \), which for \( n = 3 \) becomes \( 2 \times 3^2 \).
5. This calculation gives the total maximum electrons that can occupy the third energy level.