Which of the following determines the ground state electron configuration of an atom?

• A. The atomic mass of the element
• B. The arrangement of electrons in the lowest possible energy orbitals according to the Aufbau principle, Pauli exclusion principle, and Hund's rule
• C. The total number of neutrons in the nucleus
• D. The number of protons in the nucleus

Answer: (B)

Verified step by step guidance

1. Understand that the ground state electron configuration describes how electrons are arranged in an atom's orbitals when the atom is in its lowest energy state.
2. Recognize that the atomic mass and the number of neutrons do not directly determine electron configuration, as they relate to the nucleus rather than electron arrangement.
3. Recall that the number of protons (atomic number) determines the number of electrons in a neutral atom, which is essential for electron configuration but does not alone specify the arrangement.
4. Apply the Aufbau principle, which states that electrons fill orbitals starting from the lowest energy level to higher ones.
5. Use the Pauli exclusion principle (no two electrons can have the same set of quantum numbers) and Hund's rule (electrons fill degenerate orbitals singly before pairing) to determine the exact arrangement of electrons in orbitals.