Explain how flame emission spectroscopy can be used to identify metal ions in a sample.

A high-scoring answer should explain describe flame emission spectroscopy as an example of an instrumental method. Use method first, observation second, conclusion last: name the relevant test or measurement, state the observation, and then connect the result to Instrumental methods.

This is correct because flame colour is the evidence expected for flame test, and metal ion identity is the result that supports the conclusion. A complete answer should use the approved objective wording, include the relevant evidence, and avoid unsupported identification claims.