Correct Option
The Aufbau principle governs the order in which electrons fill atomic orbitals in the ground state of an atom. It states that electrons first occupy the orbitals with the lowest energy level before moving to higher energy orbitals. This sequential filling builds up the electron configuration of an atom. The general order of filling is 1s < 2s < 2p < 3s < 3p < 4s < 3d < 4p < 5s < 4d < 5p < 6s < 4f < 5d < 6p, and so on.
Incorrect Options
Heisenberg's uncertainty principle states that it is impossible to simultaneously determine with perfect accuracy both the position and momentum of a particle. It is a fundamental concept in quantum mechanics but does not dictate the order of orbital filling.
Hund's rule of maximum multiplicity deals with the filling of electrons within degenerate orbitals (orbitals having the same energy). It states that every orbital in a subshell is singly occupied with electrons of parallel spin before any one orbital is doubly occupied. This rule governs electron distribution within a subshell, not the order of filling different energy levels.
Pauli's exclusion principle states that no two electrons in an atom can have the same set of all four quantum numbers (principal, azimuthal, magnetic, and spin quantum numbers). This principle explains why an orbital can hold a maximum of two electrons, provided they have opposite spins, but it does not determine the order in which orbitals are filled.