Question

which rule was broken? drag pauli exclusion principle hunds rule aufbau principle

Explanation:

The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of four quantum numbers. In the given electron - filling diagram, two electrons in the same orbital have the same spin (both are shown as up - arrows), which violates the Pauli Exclusion Principle. Hund's Rule states that electrons will occupy degenerate orbitals singly before pairing up, and the Aufbau Principle states that electrons fill orbitals from the lowest energy to the highest energy. The diagram does not violate these rules.

Answer:

Pauli Exclusion Principle