Why The Shells are named as KLMN Why not ABCD Or Something else - Chemistry - Structure of Atom

Question

Why The Shells are named as KLMN Why not ABCD Or Something
else???

Kanika Dalal · Accepted Answer

Bremsstrahlung was a scientist who performed an experiment in
which, he bombarded tungsten metal with a certain frequency X-rays
and he observed that the electrons present in the lowest energy
state produced high intensity beams of light Thus, he gave the name
K-shell to the shell in the lowest energy state The name of the
consecutive shells with increasing order was kept in alphabetical
order starting from K Thus, shells in an atom in increasing order
of energy were named as K, L, M, N and so, on

Why The Shells are named as KLMN Why not ABCD Or Something else???