The Pauli Exclusion Principle is a rule about electrons in an atom.
Rule:
- No two electrons in the same atom can have the same set of four quantum numbers.
- In simpler terms: an orbital can hold a maximum of 2 electrons, and they must have opposite spins.
Why it matters:
- It explains why electrons pair up in orbitals with opposite spins.
- It also helps determine the arrangement of electrons in atoms.
Example:
In a 2p orbital, you can have:↑↓ ↑ ↑
- The first orbital has 2 electrons with opposite spins.
- The remaining orbitals have 1 electron each.
In short:
“Each electron is unique, and an orbital can hold only 2 electrons with opposite spins.”