Is there any significance in naming the electron shells as K,L,M,N...instead of A,B,C...???

Answer :

It is because of Charles Barkla. He studies the X-rays emiited by atoms when they are hit by an energy molecule/electron. He found out two types of rays; one he named as A and the other as B. he later renamed them as K and L since he thought there might be some other higher rays that required the first alphabets. But, on his further experiments, he realised that K X-ray was the hightes in the order, hence the first shell is named K. similarly, with shells L, M and N.