Question

What causes metal to emit light?​

Answer 1

Heating an atom excites its electrons and they jump to higher energy levels. When the electrons return to lower energy levels, they emit energy in the form of light. ... Every element has a different number of electrons and a different set of energy levels. Thus, each element emits its own set of colours.

Answer 2

Heat. Heating atoms causes its electrons to jump to higher energy levels; they emit energy in light form.