Because each element has an exactly defined line emission spectrum, scientists are able to identify them by the color of flame they produce. For example, copper produces a blue flame, lithium and strontium a red flame, calcium an orange flame, sodium a yellow flame, and barium a green flame..Flame tests are used to identify the presence of a relatively small number of metal ions in a compound. Not all metal ions give flame colours. For Group 1 compounds, flame tests are usually by far the easiest way of identifying which metal you have got.. - : Colored flames from strontium, cesium, sodium and lithium from left to right . Picture courtesy of the Claire Murray and Annabelle Baker from the Diamond Light Source. Confirm the colors with the elements on Table..In this lesson, we 'll be learning how to use the flame test to identify different metal ions. By the end, you 'll .