Bohr's atomic model posits electrons orbiting the nucleus in fixed energy levels. How does an electron move from one energy level to another?

Bohr's atomic model posits electrons orbiting the nucleus in fixed energy levels. How does an electron move from one energy level to another?

• A. By colliding with other electrons.
• B. By emitting or absorbing a photon with a specific energy.
• C. By slowing down and stopping.
• D. By slipping into the nucleus.

Answer: (B)

In Bohr’s model, electrons change energy levels by exchanging energy with light. When an electron drops from a higher level to a lower one, it emits a photon with energy equal to the difference between the levels. When it moves up, it must absorb a photon with that exact energy. The photon’s energy is E = hν (or E = hc/λ), so only photons with the right energy can cause the transition. Since the levels are quantized, the needed photon energy is specific. Other ideas like colliding with another electron or slowing down aren’t the mechanism described by Bohr for these transitions, and slipping into the nucleus isn’t a part of this process.

In Bohr’s model, electrons change energy levels by exchanging energy with light. When an electron drops from a higher level to a lower one, it emits a photon with energy equal to the difference between the levels. When it moves up, it must absorb a photon with that exact energy. The photon’s energy is E = hν (or E = hc/λ), so only photons with the right energy can cause the transition. Since the levels are quantized, the needed photon energy is specific. Other ideas like colliding with another electron or slowing down aren’t the mechanism described by Bohr for these transitions, and slipping into the nucleus isn’t a part of this process.