Question

electrons moving from one energy level to another emit photons. always true sometimes true never true

Explanation:

When electrons move from a higher - energy level to a lower - energy level, they emit photons. But when they move from a lower - energy level to a higher - energy level, they absorb photons. So the statement "Electrons moving from one energy level to another emit photons" is only true when the electron is moving to a lower energy level.

Answer:

Sometimes True