Read the passage given below and answer the following questions:
In spite of the predictions of stable noble gas compounds since at least 1902, unsuccessful attempts at their synthesis gave rise to the widely held opinion that noble gases are not only noble but also inert. It was not until 1962 that this dogma was shattered when Bartlett in Canada published the first stable noble gas compound `XePtF_(6)` . This discovery triggered a worldwide frenzy in this area, and within a short time span many new xenon, radon, and krypton compounds were prepared and characterized. The recent discoveries show the ability of xenon to act as a ligand . The discovery by Seppelt’s group that more than one xenon atom can attach itself to a metal center which in the case of gold leads to surprisingly stable Au- Xe bonds. The bonding in `[AuXe_(4)]^(2+)` involves 4 Xe ligands attached by relatively strong bonds to a single Au(II) center in a square planar arrangement with a Xe-Au bond length of about 274 pm This discovery provides not only the first example of multiple xenon ligands but also represents the first strong metal - xenon bond.
(Source: Christe, K. O. (2001). A renaissance in noble gas chemistry. Angewandte Chemie International Edition, 40(8), 1419-1421.)
Xe is a ___________ ligand

Options

A. ambidentate
B. bidentate
C. unidentate
D. hexadentate

Answer

To answer the question "Xe is a ___________ ligand," we will analyze the information provided in the passage step by step.

### Step-by-Step Solution:

1. **Understanding the Context**: The passage discusses the discovery of noble gas compounds, particularly focusing on xenon (Xe) and its ability to act as a ligand.

2. **Definition of Ligands**: A ligand is a molecule or ion that binds to a central metal atom to form a coordination complex. Ligands can be classified based on how many donor atoms they have.

3. **Identifying Xenon as a Ligand**: The passage mentions that xenon can act as a ligand and specifically refers to the compound `[AuXe₄]²⁺`, where four xenon atoms are attached to a gold (Au) center.

4. **Determining the Type of Ligand**: Since each xenon atom in the compound donates a single pair of electrons to the gold atom, xenon acts as a unidentate ligand (also known as monodentate), meaning it has one donor atom that binds to the metal center.

5. **Conclusion**: Based on the information provided, we can conclude that xenon (Xe) is a unidentate ligand.

### Final Answer:
Xe is a **unidentate** ligand.