The electron shells, or orbits, are named KLM because of the work of spectroscopist Charles G. Barkla, who observed X-ray emissions of different energies.
The Origin of KLM Orbit Names
Charles G. Barkla, a spectroscopist, is responsible for naming the electron shells K, L, and M. He observed that elements emitted X-rays with two distinct energy levels.
- He labeled the higher energy X-rays as type A.
- He labeled the lower energy X-rays as type B.
- He termed the innermost shell the K shell, corresponding to the A-type X-rays.
While the reference explains the origin of the K shell name, it doesn't explicitly explain why the subsequent shells were named L, M, and so on. The naming convention simply followed alphabetically after K.
