Question

A spectrum for a given element is unique for that element. why is that so?

A. No element has more than 2 electrons in the first shell.
B. Each element has an unique arrangment of electrons
C. Atoms of different elements have different masses
D. Atom nuclei Contains No electrons

Answer 1

The correct answer is B.
The electrons deal with most of the spectrum emissions. Whilst mass is technically a factor, the more precise answer would be B.