Choose the correct order of ionic radius for the following species. 

Options

A. `CI^(-) gt I^(-) gt Te^(2-) gt Ar^(+)`
B. `Te^(2-) gt I^(-) gt Cl^(-) gt Ar^(+)`
C. `I^(-) gt Te^(2-) gt Cl^(-) gt Ar^(+)`
D. `I^(-) gt Cl^(-) gt Ar^(+) gt Te^(2-)`

Answer

To determine the correct order of ionic radius for the species Cl⁻, I⁻, Te²⁻, and Ar⁺, we can follow these steps:

### Step 1: Identify the Ions and Their Charges
The ions we are dealing with are:
- Cl⁻ (Chloride ion)
- I⁻ (Iodide ion)
- Te²⁻ (Telluride ion)
- Ar⁺ (Argon cation)

### Step 2: Determine the Group and Period of Each Ion
- Cl⁻ and I⁻ are from Group 17 (the halogens).
- Te²⁻ is from Group 16 (the chalcogens).
- Ar⁺ is from Group 18 (the noble gases).

### Step 3: Analyze the Ionic Sizes
1. **Trends in Ionic Size**:
- Ionic size increases down a group due to the addition of electron shells.
- Ionic size decreases across a period from left to right due to increasing nuclear charge, which pulls electrons closer to the nucleus.

2. **Comparing the Ions**:
- Te²⁻ has the largest ionic radius because it is in Group 16 and has gained two electrons, leading to increased electron-electron repulsion.
- I⁻ is next; it is larger than Cl⁻ due to being below it in the group.
- Cl⁻ is larger than Ar⁺ because Cl⁻ has an extra electron compared to Ar⁺, which has lost one electron, reducing its size due to increased nuclear charge acting on fewer electrons.

### Step 4: Establish the Order of Ionic Radii
Based on the analysis:
- Te²⁻ > I⁻ > Cl⁻ > Ar⁺

### Conclusion
The correct order of ionic radius for the species is:
**Te²⁻ > I⁻ > Cl⁻ > Ar⁺**