OurBigBook.com $£ Sponsor €¥ 中国独裁统治 China Dictatorship 新疆改造中心、六四事件、法轮功、郝海东、709大抓捕、2015巴拿马文件邓家贵、低端人口、西藏骚乱

Madelung energy ordering rule

Looking at the energy level of the Schrödinger equation solution for the hydrogen atom, you would guess that for multi-electron atoms that only the principal quantum number would matter, azimuthal quantum number getting filled randomly.

However, orbitals energies for large atoms don't increase in energy like those of hydrogen due to electron-electron interactions.

In particular, the following would not be naively expected:

2s fills up before 2p. From the hydrogen solution, you might guess that they would randomly go into either one as they'd have the same energy
$4 s^{1}$ in potassium fills up before 3d, even though it has a higher principal quantum number!

This rule is only an approximation, there exist exceptions to the Madelung energy ordering rule.

Bibliography:

 Table of contents 139
- Exception to the Madelung energy ordering rule link Madelung energy ordering rule 40

 Ancestors

 Incoming links

Aufbau principle

 Synonyms

N + l energy ordering rule