Question

why is the SPDF syestem of atomic model used rather than K L M N {NEIL BOHRS MODEL}

Answer 1

K,L,M,N are main shell around nucleus.
s,p,d,f are sub shells present in a main shell.
for example
K main shell contain 1s^2 subshell only
M main shell contain 2s^2 2p^6 subshell.
and goes