Why do we believe that the three electrons in the 2p sublevel of nitrogen occupy different orbitals?

In nitrogen, which has three electrons in its 2p sublevel, the Pauli exclusion principle states that no two electrons can have the same set of quantum numbers. To minimize electron-electron repulsion and maximize stability, these three electrons occupy separate orbitals within the 2p sublevel, each with parallel spins. This arrangement, known as Hund's rule, leads to a lower energy configuration and greater overall stability for the atom.