The line spectra of two elements are not identical because-
(A)The element do not have the same number of neutrons
(B)They have different mass numbers
(C)Their outermost electrons are at different energy levels
(D)They have different valencies
(A)The element do not have the same number of neutrons
(B)They have different mass numbers
(C)Their outermost electrons are at different energy levels
(D)They have different valencies