What is the Electron Configuration Notation for Xenon?

What is the Electron Configuration Notation for Xenon?

Xenon is a noble gas with the atomic number 54, located in Group 18 of the periodic table. As a chemically inert element, it is widely known for its stable electron configuration. Understanding the electron configuration of xenon provides insights into its electronic structure, properties, and behavior in chemical contexts.

What is Electron Configuration?

Electron configuration refers to the arrangement of electrons in an atom’s energy levels (shells) and subshells. Electrons occupy these orbitals in a specific order, following three fundamental principles:

1. Aufbau Principle: Electrons fill orbitals starting from the lowest energy level.
2. Pauli Exclusion Principle: Each orbital can hold a maximum of two electrons with opposite spins.
3. Hund’s Rule: Electrons fill degenerate orbitals (orbitals of the same energy) singly before pairing.

Electron Configuration of Xenon

Xenon has 54 electrons. Its electron configuration is:

1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6\text{1s}^2\ \text{2s}^2\ \text{2p}^6\ \text{3s}^2\ \text{3p}^6\ \text{3d}^{10}\ \text{4s}^2\ \text{4p}^6\ \text{4d}^{10}\ \text{5s}^2\ \text{5p}^6

This can also be written in noble gas shorthand as:

[Kr] 4d10 5s2 5p6[\text{Kr}]\,\text{4d}^{10}\ \text{5s}^2\ \text{5p}^6

Here, [Kr][ \text{Kr} ] represents the electron configuration of krypton (atomic number 36), the preceding noble gas.

Breaking Down the Configuration

1. Core Electrons:
   • Electrons in the inner energy levels: [Kr]=1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6[ \text{Kr} ] = \text{1s}^2\ \text{2s}^2\ \text{2p}^6\ \text{3s}^2\ \text{3p}^6\ \text{3d}^{10}\ \text{4s}^2\ \text{4p}^6.
2. Valence Electrons:
   • Electrons in the outermost shell (5th energy level): 5s2 5p6\text{5s}^2\ \text{5p}^6.
3. Subshell Filling:
   • The 4d10\text{4d}^{10} subshell is completely filled before the 5p6\text{5p}^6, reflecting xenon’s position in Period 5 of the periodic table.

Why is Xenon Stable?

Xenon’s electron configuration ends with a fully filled 5s\text{5s} and 5p\text{5p} subshell. This complete octet in its outermost shell makes xenon chemically stable and inert, a characteristic of noble gases.

Applications of Xenon

Understanding xenon’s electron configuration helps explain its unique properties and applications:

1. Lighting: Used in high-intensity discharge lamps, such as xenon arc lamps and automobile headlights.
2. Medical Imaging: Utilized in xenon gas anesthetics and in imaging techniques like MRI.
3. Space Exploration: Employed as a propellant in ion thrusters due to its inert nature.