From the change in the P2O5 and NaOH trap masses, determine the masses of H2O and CO2 produced. Be careful to use the change in mass of each trap for just before, and just after, the unknown sample is combusted. (You should not use the initial masses of the two traps at the start of the experiment.)

Answer;

-Emit energy as they return to lower energy levels.

Explanation;

-A characteristic color of light is emitted by these ions in the flame when the electrons emit energy as they return to lower energy levels.

-The metal ions do absorb energy, and the electrons are boosted to higher energy levels, but they emit that energy as they fall to lower levels, and it is the photons of light they are emitting that can be seen.