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 spin - up), which violates the Pauli Exclusion Principle. Hund's Rule is about maximizing the number of unpaired electrons with parallel spins in degenerate orbitals, and the Aufbau Principle is about filling orbitals in order of increasing energy.

Answer:

Pauli Exclusion Principle