Question

The line spectra of two elements are different because:

• A. the elements do not have the same number of neutrons
• B. they have different mass numbers
• C. their outermost electrons are at different energy levels
• D. all of the above

Answer 1

Answer: (C)

their outermost electrons are at different energy levels

For two different elements, their valence electrons are at different energy levels, so when an electron makes a transition to another level, different type of spectral line is observed.