Answer:
Exposing it to a flame to see if it catches on fire
Step-by-step explanation:
This is known as the flame test; The flame test is used to visually determine the identity of an unknown metal ions in a compound.
With the help of the flame test, the scientist can make use it as a qualitative test that guides him in making decision when trying to pinpoint the identity of the solid.
When the solid is exposed to flame, there may be a characteristic color given off that is visible to the naked eye (Note: Not all solids give flame colors).
The colors observed during the flame test result from the excitement of the electrons caused by the increased temperature. When the atoms of the electron are excited, for instance by, their electrons are able to move from their ground state to higher energy levels.
With this, the scientist can draw a valid conclusion.