How many orbitals are present in the third principal energy level (n = 3) of an atom?

• A. 18
• B. 6
• C. 9
• D. 3

Answer: (C)

Verified step by step guidance

1. Recall that the number of orbitals in a principal energy level (shell) is given by the formula \(n^2\), where \(n\) is the principal quantum number.
2. Identify the principal quantum number for the problem, which is \(n = 3\).
3. Calculate the total number of orbitals by squaring \(n\): \$3^2$.
4. Understand that each orbital can hold up to 2 electrons, but the question only asks for the number of orbitals, not electrons.
5. Conclude that the third principal energy level contains \(9\) orbitals.