Question

In the Bohr model, what happens when an electron makes a transition between orbits?

Short answer

When an electron transitions between orbits in the Bohr model, it either absorbs or emits energy in the form of a photon, corresponding to the difference in energy between the initial and final orbits.

Step-by-step solution

Understand the Bohr Model

In the Bohr model of the atom, electrons orbit the nucleus in specific paths, or energy levels, without emitting radiation. Each path corresponds to a certain energy level.

Describe the Transition Process

When an electron makes a transition between orbits, it is moving from one energy level to another. The transition can be an 'excitation' when it absorbs energy and jumps to a higher energy level, or 'emission' when it loses energy and falls to a lower energy level.

Explain Energy Absorption or Emission

During the transition between orbits, if the electron absorbs energy (excitation), it will absorb a photon with energy equal to the difference in energy between the levels. Conversely, if the electron loses energy (emission), it will emit a photon whose energy is the difference between the two levels.

Key concepts

Energy levels in atoms

Atoms are the basic units of matter and consist of a dense nucleus surrounded by a cloud of electrons. The electrons in an atom are not just scattered around the nucleus; they occupy specific regions known as energy levels or shells. These energy levels are like the rungs of a ladder, with each successive level further away from the nucleus holding electrons at progressively higher energies.

In the context of the Bohr model, these energy levels are quantized, which means that an electron cannot exist between the set levels; it must be on one of the rungs. Think of it as being allowed to stand on the first or second step of the ladder but not on the air in between. The energy of each level is represented by the formula: \( E_n = -\frac{R_H}{n^2} \) where \( R_H \) is the Rydberg constant and \( n \) is the principal quantum number, which indicates the energy level's number.

Electron excitation

Electron excitation is a process that occurs when an electron inside an atom absorbs energy and jumps from a lower to a higher energy level. This is similar to a person using energy to jump to a higher step on a ladder. In the atom, this energy can come from various sources, such as light (photons) or collisions with other particles.

When an electron is excited, it absorbs a photon with just the right amount of energy to make the transition. This energy must match the difference between the electron's current energy level and the one it is jumping to, obeying the law of conservation of energy. The mathematical form of this energy difference is expressed as \( \Delta E = E_{final} - E_{initial} \) where \( E_{final} \) and \( E_{initial} \) are the energies of the electron in the final and initial levels, respectively. This process is crucial for many phenomena in physics and chemistry, including spectroscopy and the functioning of lasers.

Photon emission and absorption

When discussing photons in the context of the Bohr model, we're essentially talking about packets of light energy that electrons can either emit or absorb. These transitions between energy levels within atoms are responsible for the phenomenon of photon emission and absorption.

During photon emission, an electron drops from a higher energy level to a lower one, releasing energy in the form of a photon. The energy of this photon is precisely equal to the energy difference between the two levels. On the other hand, photon absorption happens when an electron gains energy by absorbing a photon, allowing it to move up to a higher energy level. This is what generates the diverse colors we witness in fireworks or neon signs, where each color represents a specific photon energy, thus linking to a unique transition between energy levels. These processes are fundamental to our understanding of atomic behavior and are integral in technologies such as photovoltaic cells and various forms of spectroscopy.