If X is a member of chalcogen family, the highest stability of `X^(-2)` is exhibited by

Options

A. Oxygen
B. Selenium
C. Tellurium
D. Sulphur

Answer

To solve the question regarding which member of the chalcogen family exhibits the highest stability of the `X^(-2)` ion, we will follow these steps:

### Step 1: Identify the Chalcogen Family
The chalcogen family corresponds to Group 16 of the periodic table. The elements in this group are:
- Oxygen (O)
- Sulfur (S)
- Selenium (Se)
- Tellurium (Te)

### Step 2: Understand the Concept of Stability of Ions
The stability of an ion, particularly the `X^(-2)` ion, depends on the ability of the atom to attract and hold onto additional electrons. This ability is influenced by factors such as atomic size and effective nuclear charge.

### Step 3: Analyze Atomic Size and Effective Nuclear Charge
As we move down the group from oxygen to tellurium:
- The atomic size increases due to the addition of electron shells.
- The distance between the nucleus and the outermost electrons increases, which reduces the effective nuclear charge experienced by these outer electrons.

### Step 4: Determine the Effect on Ion Stability
With an increase in atomic size:
- The ability of the nucleus to attract additional electrons decreases.
- Therefore, the stability of the `X^(-2)` ion decreases as we move down the group.

### Step 5: Compare the Elements
- **Oxygen**: Smallest atomic size, highest effective nuclear charge, and thus the highest ability to stabilize the `O^(-2)` ion.
- **Sulfur**: Larger than oxygen, less stable `S^(-2)` ion.
- **Selenium**: Even larger, further decreased stability for `Se^(-2)`.
- **Tellurium**: Largest atomic size in this group, lowest stability for `Te^(-2)`.

### Conclusion
Based on the analysis, the element in the chalcogen family that exhibits the highest stability of the `X^(-2)` ion is **Oxygen (O)**.

### Final Answer
**Oxygen (O)** exhibits the highest stability of `X^(-2)`.

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