Chemistry – Experimental techniques and chemical analysis - Identification of ions and gases | e-Consult

The most likely cation present is barium (Ba²⁺). This is because barium compounds produce a characteristic green flame when tested with a flame test. The flame test works by exciting the electrons in the metal cation. The energy levels of the electrons are specific to each element. Barium has specific energy levels that correspond to the emission of green light when the electrons return to their ground state. Therefore, the presence of a green flame strongly indicates the presence of barium ions in the compound.