Final answer:
The angle at which the flame should contact the metal depends on the line emission spectra of the metals. Each metal salt has a uniquely colored flame based on the arrangement of electrons.
Step-by-step explanation:
The angle at which the flame should contact the metal depends upon the line emission spectra of the metals. Each metal salt has a uniquely colored flame which is a result of the arrangement of electrons in the metal.
By observing the color of the flame, scientists can identify the metal present.