Physics
Quantum Numbers (n, l, m, s)
Quick fact
No two electrons in an atom can have the same set of four quantum numbers—this is the Pauli exclusion principle, which shapes the entire periodic table.
Why this is interesting
You know atoms have electrons buzzing around a nucleus, but what prevents them from crashing into it, and how do they arrange themselves so neatly into the periodic table? The answer lies in four simple numbers—the quantum numbers.