Question

Line spectrum is characteristic of:
a.) Molecules
b.) Atoms
c.) Radicals
d.) None of the above

Answer 1

Hint: "Line spectrum" generally implies that we are talking about lines with wavelengths that fall into the range of the visible spectrum. Now you can easily answer this one.

Complete step by step answer:
The line spectrum is the result of the interaction between a quantum system and a single photon. When a photon has about the right amount of energy to allow a change in the energy state of the system, the photon is absorbed.
The photon will be spontaneously re-emitted, either in the same frequency as the original or in a cascade, where the sum of the energies of the photons emitted will be equal to the energy of the one absorbed.

When atoms are excited they emit light of certain wavelengths that correspond to different colors and the emitted light is observed as a series of colored lines with dark spaces in between. This series of colored lines is called a line or atomic spectra.
Each element produces a unique set of spectral lines and since no two elements emit the same spectral lines, elements can be identified by their line spectrum.
Here we can see electron transitions for hydrogen atom -

Therefore, we can conclude that the correct answer to this question is option B.

Note: We should know that spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected "fingerprints" of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible.