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 principal quantum numbers. These higher energy states are less stable than the ground state and the electrons will eventually return to the lower energy ground state, often releasing energy in the form of photons.

5 Must Know Facts For Your Next Test

1. Excited states are higher energy levels that electrons can occupy within an atom or molecule, but they are less stable than the ground state.
2. Electrons can be promoted to excited states by absorbing energy, such as from the absorption of a photon or through collisions with other particles.
3. When electrons in excited states return to the ground state, they release the excess energy in the form of a photon, which can be observed as light emission.
4. The specific energy levels and transitions between them are governed by the principles of quantum mechanics and are unique to each type of atom or molecule.
5. Excited states play a crucial role in various applications, including atomic and molecular spectroscopy, laser technology, and the understanding of chemical reactions.

Review Questions

• Explain how the Heisenberg Uncertainty Principle relates to the concept of excited states.
  • The Heisenberg Uncertainty Principle states that the more precisely the position of a particle is known, the less precisely its momentum can be known, and vice versa. This principle applies to the behavior of electrons in atoms and molecules, including their transition between energy levels. When an electron is in an excited state, its position and momentum are less precisely known, which is a consequence of the uncertainty principle. The transition between excited states and the ground state involves the release or absorption of energy, which can be observed as the emission or absorption of photons.
• Describe how the applications of atomic excitations and de-excitations are related to the concept of excited states.
  • Excited states are central to the applications of atomic excitations and de-excitations. When atoms or molecules absorb energy, their electrons can be promoted to higher energy levels, or excited states. These excited states are unstable, and the electrons will eventually return to the ground state, releasing the excess energy in the form of a photon. This process of de-excitation is the basis for various applications, such as atomic and molecular spectroscopy, where the emission or absorption of specific wavelengths of light can be used to identify the presence and characteristics of different atoms and molecules. Additionally, the controlled excitation and de-excitation of atoms is the foundation for laser technology, where the stimulated emission of photons from excited states is used to amplify light and generate coherent beams.
• Analyze how the concept of excited states is crucial for understanding the behavior of atoms and molecules in the context of quantum mechanics.
  • The concept of excited states is fundamental to the understanding of atomic and molecular behavior within the framework of quantum mechanics. Quantum mechanics describes the discrete energy levels that electrons can occupy within an atom or molecule, and the transitions between these energy levels are what define the excited states. The ability of electrons to be promoted to higher energy levels, or excited states, and their subsequent de-excitation back to the ground state, is central to the quantum mechanical description of atomic and molecular structure and dynamics. This includes the absorption and emission of photons, the formation of chemical bonds, and the understanding of various spectroscopic techniques used to probe the properties of atoms and molecules. Without the concept of excited states, the quantum mechanical description of the behavior of matter at the atomic and molecular scale would be incomplete.

Related terms

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

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.

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 in the form of a photon.