Which ion produces a green flame during a flame test?

During a flame test, different metal ions emit characteristic colors when heated, due to the excitation of their electrons. The presence of barium ions (Ba²⁺) is specifically associated with the production of a green flame.

When barium is heated, its electrons are excited to a higher energy level. As these excited electrons return to their original energy levels, they release energy in the form of light. The wavelength of this emitted light corresponds to the green portion of the spectrum, which is perceived as a green flame.

In contrast, other ions produce different colors; for example, lithium produces a red flame, sodium emits a bright yellow flame, and calcium generates an orange-red flame. Understanding these specific reactions is crucial for identifying elements through flame tests in a laboratory setting.