Question

What is difference between K L M N O shells and S P D F shells?

Answer 1

K,L, M, N, O- are the shells present (orbitals) in an atom.
Whereas s,p,d,f - are the sub-shells present in each of the K,L,M,N,O -shells.
K-Shell contains only s- subshell.
L-Shell contains s, p-subshells.
M-Shell contains s,p,d-subshells.
N-Shell contains s,p,d,f-subshells.

Answer 2

KLMN are electronic shells. 1it indicates the number of electrons and atoms. where as  spdf are sub shells and it can be further divided into sub shells individually.