When an electron relaxes from an excited state to the ground state in an atom, what is emitted?

• A. A photon of specific energy
• B. A neutron
• C. A proton
• D. An electron

Answer: (A)

Verified step by step guidance

1. Understand that when an electron in an atom moves from a higher energy level (excited state) to a lower energy level (ground state), energy must be released because the electron is losing energy.
2. Recall that energy in atoms is quantized, meaning electrons can only exist in specific energy levels, and transitions between these levels involve discrete amounts of energy.
3. Recognize that the energy lost by the electron during this transition is emitted in the form of electromagnetic radiation, specifically a photon.
4. Know that the energy of the emitted photon corresponds exactly to the difference in energy between the excited state and the ground state, which determines the photon's wavelength and frequency.
5. Conclude that the correct emission during this relaxation process is a photon of specific energy, not particles like neutrons, protons, or electrons.