Aufbau principle — Science definition
Electrons fill the lowest-energy available sublevel first before moving to higher ones.
Where it is taught
- Electron Configuration — Atoms, Electrons & Periodicity, Physical Science: Chemistry, Grade 11
Questions using aufbau principle
Problem 1
Briefly state, in your own words, what the Aufbau principle, the Pauli exclusion principle, and Hund's rule each say.
Answer and explanation
Aufbau: fill the lowest-energy sublevels first. Pauli: no orbital can hold more than two electrons, and they must have opposite spins. Hund: within a sublevel, electrons spread out one per orbital before any orbital gets a second electron.
Taught alongside
- energy level (n)
- sublevel
- orbital
- electron configuration
- Pauli exclusion principle
- Hund's rule
- valence electrons