Problem 12 - General Chemistry: Principles and Modern Applications

Question

Provide an explanation for the inability of \(\mathrm{O}_{2}\) to react directly with xenon.

Step-by-Step Solution

Answer

Xenon, being a noble gas, has a fully filled outermost electron shell, making it stable and less reactive. Oxygen, particularly \(\mathrm{O}_{2}\), is also stable and doesn't readily react. Because of the stability of both, \(\mathrm{O}_{2}\) cannot react directly with xenon under standard conditions.

Step 1: Understanding the nature of xenon

Xenon is a noble gas. The noble gases, are located in group 18 of the periodic table. These elements are characterized by having their outermost electron shells fully occupied. Specifically for xenon, its outermost shell has a stable electron configuration with 8 electrons.

Step 2: Explaining the non-reactivity of xenon

Because xenon, like other noble gases, has a full set of electrons in its outermost shell, it is generally unreactive. The electron shell structure of xenon makes it stable and not eager to accept or donate electrons, impeding bond formation. This contributes to its inability to directly react with other elements, including oxygen.

Step 3: Understanding the nature of oxygen

Elemental oxygen exists as \(\mathrm{O}_{2}\), a diatomic molecule. This molecule is stable and does not readily break apart to form other compounds.

Step 4: Explaining the inability of \(\mathrm{O}_{2}\) to react directly with xenon

Given the highly stable nature of both xenon and oxygen, neither has a tendency to break their current stable state and form a new bond. Therefore, \(\mathrm{O}_{2}\) doesn't react directly with xenon under standard conditions.

Key Concepts

Xenon Reactivity

Xenon is a member of the noble gases group in the periodic table. These gases are distinctive because their electron configurations are full in their outermost shell. For xenon, this configuration consists of 8 electrons, which contribute to its stability. In simple terms, having a complete outer shell means xenon is not "looking" for more electrons, and it also doesn’t want to lose any. This makes xenon very reluctant to participate in chemical reactions under normal circumstances. If an element is not going to gain or lose electrons, then it's unlikely to bond with other elements. However, while xenon is considered inert, it can form compounds, but only under very specific, often high-energy conditions. So, the general notion of xenon as unreactive is primarily due to its stable electron configuration.

Oxygen Stability

Oxygen, in its most common form, exists as a molecule made up of two oxygen atoms, known scientifically as \(O_{2}\). Each oxygen atom shares electrons with the other, creating a strong double bond between them. This gives oxygen molecules a stable structure that does not easily dissociate. This stability is essential for life, as \(O_{2}\) is the form of oxygen that most living organisms use for respiration. The strength of the bond in molecular oxygen makes it resistant to reacting with other elements unless those elements can provide sufficient energy to overcome the bond energy. Thus, oxygen does not simply "give up" its structure in the presence of other substances, like xenon, without a driving force.

Electron Shell Configuration

An understanding of electron shell configuration helps explain the behavior of both xenon and oxygen. The electrons in an atom orbit the nucleus in distinct layers called shells. Each shell can hold only a specific number of electrons. Having a full outer shell is the key to stability in most elements. In a full shell, there's little to no tendency for gaining or losing electrons, as this would disturb the balance and stability. For xenon, its outer shell is full with 8 electrons, while for oxygen in \(O_{2}\), the two atoms efficiently share their electrons to maintain a stable configuration. When both elements are stable, they have low motivation to bond with other elements or reactions, contributing greatly to their overall non-reactivity. Therefore, electron shell configuration is crucial for understanding why some elements, like xenon and oxygen in its diatomic form, do not react easily.