Question

Explain what is meant by the term "excited state" as it applies to an electron. Is an electron in an excited state higher or lower in energy than an electron in the ground state? Is an electron in an excited state more or less stable than an electron in the ground state?

Short answer

The term "excited state" refers to an electron in a higher energy subshell than its ground state, which is the lowest energy state. An electron in an excited state has higher energy and is less stable than an electron in the ground state, as electrons naturally tend to occupy lower energy states for stability. Excited electrons are likely to transition back to their ground state by emitting a photon.

Step-by-step solution

Definition of Excited State

An excited state is a state in which an electron is in a higher energy subshell than its ground state, which is the lowest energy state. When an electron absorbs energy, such as from a photon, it can jump to a higher energy subshell, resulting in an excited state.

Excited State vs. Ground State: Energy

An electron in an excited state has higher energy than an electron in the ground state. This is because the electron in an excited state has absorbed energy to move to a higher energy subshell, while the ground state represents the electron's lowest energy state.

Excited State vs. Ground State: Stability

An electron in an excited state is less stable than an electron in the ground state. This is because electrons naturally tend to occupy the lowest possible energy states, which are more stable. Atoms with electrons in excited states are likely to transition back to their ground state by emitting energy in the form of a photon.

Key concepts

Electron Energy Levels

Electrons within an atom exist in specific energy levels or shells. These energy levels represent the different amounts of energy that an electron can have.
Imagine these levels as steps on a ladder, where each step represents a higher energy level as you move upwards.
Electrons are generally found in the lowest possible energy level, known as the ground state.

• Each energy level can hold a certain number of electrons.
• Lower energy levels are filled before higher ones are occupied.
• Electrons move between energy levels when they absorb or release energy.

These energy levels are quantized, meaning electrons cannot exist between these steps or levels. They shift from one level to another by either absorbing energy to move to a higher level or releasing energy to drop to a lower one. This is the basis of how electrons transition into excited states.

Ground State

The ground state is the lowest energy state of an electron within an atom. In this state, the electron occupies the smallest possible orbit, or energy level, closest to the nucleus. This proximity ensures it has the least energy and is in its most stable form.
Electrons in their ground state are less likely to move spontaneously because they are already in the lowest energy configuration.

• The ground state is typically more stable than excited states due to minimized energy.
• Atoms with electrons in the ground state are more likely to maintain their current state unless energy is introduced.
• When electrons are excited by energy, such as from heat or light, they may move to a higher energy level, temporarily exiting the ground state.

After being excited, electrons tend to return to the ground state by releasing energy, often in the form of light. This process is common in many natural phenomena and technologies, such as the emission of light in neon signs or chemical reactions that emit light.

Atomic Stability

Atomic stability refers to an atom's tendency to maintain its current energy state. This stability is greatly influenced by the energy levels of electrons.
Electrons strive to find the lowest energy configuration possible, which generally corresponds to increased stability.
When electrons are in their ground states, atoms are in their most stable configurations.

• Stability is highest when electrons occupy the lowest energy levels available.
• An excited electron represents a higher energy and a less stable state.
• Atoms naturally seek to return to a stable ground state, often emitting energy in the process.

The concept of stability is crucial for understanding chemical reactions and the behavior of elements. Stable atoms are less likely to react with others, whereas those with electrons in excited states may actively seek interactions to release excess energy and return to stability.