Question

WHY are the shells in which the electrons revolve are named as K,L,M,N and not A,B,C,D or something else????

Answer 1

He named the innermost shell has k shell because he noticed that the X-rays emitted two types energies. These energies were named as type A that is higher energy X-ray and type B that is lower energy X-ray. Later these energiers were named with different alphabets.