Which of the following electron configurations violates the Aufbau Principle?
The Aufbau Principle states that electrons fill orbitals in order of increasing energy, starting with the lowest energy level. In option B, the orbital is being filled before the 2p orbital, which violates the Aufbau Principle. Hence option B is correct.
Option A is correct because it follows the Aufbau Principle, where the 1s, 2s, and 2p orbitals are filled before the 3s orbital. Hence option A is incorrect.
Option C is correct because it follows the Aufbau Principle, but it violates the Pauli Exclusion Principle because there are two electrons with the same spin in the 2p sublevel. Hence option C is incorrect.
Option D is correct because it follows the Aufbau Principle, but it violates the Pauli Exclusion Principle because there is only one electron in the 2s orbital. Hence option D is incorrect.