Question

1. below are diagrams for the bright line spectra of four elements and the spectrum of a mixture of unknown gases.

li
h
he
na
unknown
a. which element(s) are not present in the unknown?
b. which element(s) are in the unknown?

Explanation:

Bright line spectra are unique to each element; all lines of a present element must match the unknown's spectrum.

1. For part a: Compare each element's spectrum to the unknown. Li has lines not found in the unknown, so it is absent.
2. For part b: Check that all lines of H, He, and Na are present in the unknown's spectrum, so these elements are present.

Answer:

a. Li
b. H, He, Na