Final answer:
An electron configuration that includes more than two electrons in an orbital, such as 1s² 2s² 2p⁶ 3s², represents a violation of the Pauli Exclusion Principle, which dictates that an atomic orbital can hold a maximum of two electrons with opposite spins.
Step-by-step explanation:
The Pauli Exclusion Principle states that no two electrons can have the same set of four quantum numbers. Hence, within an atomic orbital, a maximum of two electrons can exist, and they must have opposite spins. We can analyze the following electron configurations to determine if they violate the Pauli Exclusion Principle:
- 1s² 2s² 2p⁵
- 1s² 2s² 2p⁶
- 1s² 2s² 2p³
- 1s² 2s² 2p⁶ 3s²
All of these configurations adhere to the Pauli Exclusion Principle, except option (b) 1s² 2s² 2p⁶ 3s², which includes an extra pair of electrons in the 3s orbital, making a total of four electrons. This does not comply with the rule stating that an orbital can hold a maximum of two electrons with opposite spins.