key term - Excited States

Definition

Excited states refer to the higher energy levels that an atom or molecule can occupy when electrons are promoted to orbitals with greater energy than the ground state. These elevated energy levels are temporary and the system will eventually return to the more stable ground state configuration.

5 Must Know Facts For Your Next Test

1. Excited states are formed when an atom or molecule absorbs energy, such as from a photon or collision, causing an electron to be promoted to a higher energy level.
2. The energy difference between the ground state and the excited state determines the specific wavelength of light that can be absorbed or emitted when the electron transitions.
3. Excited states are inherently unstable, and the system will spontaneously return to the ground state through the emission of a photon or other energy-releasing process.
4. The Bohr model of the atom describes the electron transitions between discrete energy levels, which correspond to the excited states of the atom.
5. The lifetime of an excited state is typically very short, on the order of nanoseconds to microseconds, before the system relaxes back to the ground state.

Review Questions

• Explain how the Bohr model of the atom relates to the concept of excited states.
  • The Bohr model of the atom describes the electron as occupying discrete energy levels around the nucleus. According to this model, electrons can be promoted to higher energy levels, known as excited states, by the absorption of energy. The energy difference between the ground state and the excited state corresponds to the specific wavelength of light that can be absorbed or emitted when the electron transitions between these levels.
• Analyze the role of excited states in the emission and absorption of light by atoms.
  • Excited states play a crucial role in the emission and absorption of light by atoms. When an atom absorbs energy, such as from a photon, an electron is promoted to a higher energy level, or excited state. The atom is then in an unstable configuration and will spontaneously return to the ground state by emitting a photon with a specific wavelength, corresponding to the energy difference between the excited state and the ground state. This process of absorption and emission of light is the basis for many spectroscopic techniques used to study the structure and properties of atoms and molecules.
• Evaluate the significance of the lifetime of an excited state in the context of atomic and molecular processes.
  • The lifetime of an excited state is a critical factor in understanding and predicting the behavior of atoms and molecules. Excited states are inherently unstable and have a finite lifetime, typically on the order of nanoseconds to microseconds, before the system relaxes back to the ground state. This short lifetime is significant because it determines the rate at which the system can undergo various processes, such as the emission of a photon, the transfer of energy to other molecules, or the initiation of chemical reactions. The lifetime of an excited state is influenced by factors like the strength of the interactions between the electron and the nucleus, as well as the surrounding environment, and it is a key parameter in the study of atomic and molecular spectroscopy, photochemistry, and other related fields.

Related terms

Ground State: The lowest possible energy level of an atom or molecule, where electrons occupy the most stable configuration.

Electron Transition:

The process by which an electron moves from one energy level to another within an atom or molecule, either by absorbing or emitting energy.

Quantum Mechanics:

The branch of physics that describes the behavior of matter and energy on the atomic and subatomic scale, including the concept of discrete energy levels.