According to the Pauli exclusion principle, what can be said about electrons in the same atom?

The Pauli exclusion principle states that no two electrons in the same atom can have the same set of all four quantum numbers. Quantum numbers are used to describe the unique quantum state of an electron in an atom, including its energy level, orbital shape, orientation, and spin. Each electron in an atom is characterized by a unique combination of these quantum numbers.

When two electrons occupy the same orbital (i.e., they are in the same energy level and orientation), they can still differ in their spin quantum number. Therefore, while they can share the same energy level and specific orbital, they must have opposite spins to comply with the Pauli exclusion principle. This principle is fundamental to understanding electron configurations and the behavior of atoms in chemical bonding and interactions.

Thus, stating that electrons cannot have the same four quantum numbers accurately reflects this principle, emphasizing that each electron must have its own unique state within an atom.