Why do only certain colors appear in the emission spectrum of a single element?

• A. Because the nucleus of the atom emits light at random wavelengths.
• B. Because the temperature of the element determines which colors are visible.
• C. Because the element absorbs all colors except a few that are reflected.
• D. Because electrons in the atom can only occupy specific energy levels, and the emitted light corresponds to transitions between these levels.

Answer: (D)

Verified step by step guidance

1. Understand that the emission spectrum of an element arises from electrons transitioning between discrete energy levels within an atom.
2. Recall that electrons in an atom can only exist in specific, quantized energy states, not in between these levels.
3. When an electron drops from a higher energy level to a lower one, it emits a photon of light with energy equal to the difference between these two levels.
4. Since the energy of the photon determines its wavelength (color) by the relation \(E = \frac{hc}{\lambda}\), only certain wavelengths corresponding to allowed energy transitions are emitted.
5. Therefore, the emission spectrum shows only specific colors (wavelengths) characteristic of the element, rather than a continuous range.