# Origin of electron quantum number designations **URL:** \ **Category:** Factual Questions\ **Created:** [November 29, 2002, 7:30am UTC](https://boards.straightdope.com/t/origin-of-electron-quantum-number-designations/139471 "2002-11-29T07:30:18Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [November 29, 2002, 7:30am UTC](https://boards.straightdope.com/t/origin-of-electron-quantum-number-designations/139471/1 "2002-11-29T07:30:18Z")
What are the exact origins of the letter designations of the quantum numbers used for electron energy states? I’m referring to the n-l-m-s system, and the K-L-M-N system that is sometimes used to substitute for the n=1,2,3,4,5,6 system. Thanks. ---
**Author:** ![Cardinal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cardinal/32/4000_2.png) [@Cardinal](https://boards.straightdope.com/u/Cardinal)\ **Post date:** [November 30, 2002, 2:26am UTC](https://boards.straightdope.com/t/origin-of-electron-quantum-number-designations/139471/2 "2002-11-30T02:26:52Z")
Shameless bump. ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [November 30, 2002, 2:51am UTC](https://boards.straightdope.com/t/origin-of-electron-quantum-number-designations/139471/3 "2002-11-30T02:51:50Z")
No need to be apologetic about this, it’s a bloody good question. Pais in _Inward Bound_ (Oxford, 1986, p273) indicates that the historical order of introduction was _n,l,m_, which does just beg the question _why_? My second guess might be to look in the short history/memoir Friedrich Hund wrote about quantum physics in the 1920s, but it’s years since I’ve looked at that.