According to the Pauli exclusion principle, how many electrons can occupy a single orbital?

• A. 4
• B. 1
• C. 6
• D. 2

Answer: (D)

Verified step by step guidance

1. Recall that the Pauli exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers.
2. Understand that an orbital is defined by a specific set of quantum numbers (n, l, m_l), which describe its size, shape, and orientation.
3. Since electrons have a quantum number called spin (m_s), which can be either +1/2 or -1/2, each orbital can hold electrons with opposite spins.
4. Therefore, a single orbital can accommodate a maximum of two electrons, each with opposite spins to satisfy the Pauli exclusion principle.
5. Conclude that the correct number of electrons that can occupy a single orbital is 2.