According to the Pauli Exclusion Principle, what must be true about electrons in the same orbital?

According to the Pauli Exclusion Principle, which is a fundamental principle in quantum mechanics, no two electrons in an atom can have identical sets of quantum numbers. When electrons occupy the same orbital, they must exhibit properties that differentiate them, specifically regarding their spins.

Each orbital can hold a maximum of two electrons, and these two electrons must have opposite spins. This means one electron will have a spin quantum number of +1/2, while the other will have a spin quantum number of -1/2. This requirement of opposite spins ensures that the quantum state of each electron is unique, thereby adhering to the Pauli Exclusion Principle.

Understanding this principle is crucial in context, as it explains the arrangement of electrons in orbitals and helps define the structure of the periodic table, chemical bonding, and the behavior of various elements.