Question

note: to answer some of the questions, it may help to reference a periodic table. what choice best describes an emission line spectrum? when excited electrons of an atom “fall” back to ground state, they emit light. when the electrons of an atom become excited, they emit light. when excited electrons of an atom “fall” to ground state, they emit distinct lines of colored light. when the electrons of an atom are excited, they emit distinct lines of colored light.

Explanation:

An emission - line spectrum occurs when excited electrons in an atom "fall" back to the ground state. As they do so, they emit distinct lines of colored light corresponding to specific energy differences. Just getting excited doesn't result in light emission, and it's the return to the ground state that gives the characteristic lines.

Answer:

When excited electrons of an atom "fall" to ground state, they emit distinct lines of colored light.