The bright-line spectrum of an element in the gaseous phase is produced as 1. protons move from lower energy states to higher energy states 2. protons move from higher energy states to lower energy states 3. electrons move from lower energy states to higher energy states 4. electrons move from higher energy states to lower energy states

4. Electrons move from high energy states to lower energy states.

Bright-line emission spectra are produced for atoms in hot gaseous state when electrons move excitedly from higher energy levels to lower energy levels and emit discrete quantities of energies while they transition. This emitted energy forms bright and discrete lines in the spectra, forming a characteristic bright-line spectrum for each atom.