According to the Aufbau principle, which of the following electron configurations is correct for a ground-state nitrogen atom?
Explanation: The Aufbau principle states that electrons fill orbitals in order of increasing energy, starting with the lowest energy level. The electron configuration of nitrogen is . This configuration follows the Aufbau principle, where electrons fill the 1s, 2s, and 2p orbitals in order of increasing energy. Hence option A is the correct answer.
Option (B) is incorrect because the 3s orbital has a higher energy than the 2p orbital, so it should be filled after the 2p orbitals are filled. Hence option B is incorrect.
Option (C) Option C is incorrect because it has four electrons in the 2p sublevel, which violates the Pauli Exclusion Principle. Hence option C is incorrect.
Option (D) Option D is incorrect because it has only one electron in the 2s orbital, which violates the Hund’s Rule of Maximum Multiplicity. Hence option D is incorrect.