Identify the electron configuration that represents an atom in an excited state.
The Correct Answer and Explanation is:
To identify the electron configuration of an atom in an excited state, it’s important to understand what an excited state is and how it differs from the ground state.
Ground State Electron Configuration:
The ground state of an atom refers to the lowest energy configuration where the electrons are in the most stable arrangement possible. For example, sulfur (S) in its ground state has the following electron configuration:
S (Z=16):1s22s22p63s23p4\text{S (Z=16)}: 1s^2 2s^2 2p^6 3s^2 3p^4S (Z=16):1s22s22p63s23p4
This configuration corresponds to the atom’s lowest energy arrangement. In the ground state, the electrons fill orbitals in a specific order according to the Aufbau principle, the Pauli exclusion principle, and Hund’s rule.
Excited State:
An excited state occurs when an atom absorbs energy, and one or more of its electrons move from a lower energy orbital to a higher energy orbital. In the excited state, the electron configuration will be different from the ground state. This configuration typically shows an electron “jumping” to a higher orbital than where it would be in the ground state.
For example, if a sulfur atom (with 16 electrons) absorbs energy, one of its 3p electrons could be excited to a higher orbital, such as a 4s orbital. In this case, the electron configuration of sulfur in an excited state could look like:
S (excited state):1s22s22p63s23p34s1\text{S (excited state)}: 1s^2 2s^2 2p^6 3s^2 3p^3 4s^1S (excited state):1s22s22p63s23p34s1
This configuration is an example of an excited state because one of the 3p electrons has been promoted to the 4s orbital. It’s important to note that, in an excited state, the electron’s energy increases, and the atom is no longer in its most stable form.
Explanation of Electron Promotion:
In an excited state, electrons can be promoted to higher orbitals when they absorb energy. The exact configuration depends on which electrons are excited and to which orbitals they are promoted. The atom is in a higher energy state, which is usually temporary, and it will return to the ground state after the energy is released.
Thus, the correct answer would be the configuration where one or more electrons are found in higher orbitals than in the ground state.
