Size of the iodine species following the order:

Options

A. `I^(o+)gtI^(Theta)gtI`
B. `IgtI^(o+)gtI^(Theta)`
C. `IgtI^(Theta)gtI^(o+)`
D. `I^(Theta)gtIgtI^(o+)`

Explanation

To determine the size of iodine species (I, I-, and I+), we need to analyze how the addition or removal of electrons affects the size of the species.

### Step-by-Step Solution:

1. **Understanding the Species**:
- We have three species to compare: I (iodine atom), I- (iodide ion), and I+ (iodine cation).
- I is the neutral atom, I- is the anion formed by gaining an electron, and I+ is the cation formed by losing an electron.

2. **Analyzing I- (Iodide Ion)**:
- When iodine gains an electron to become I-, it experiences an increase in electron-electron repulsion due to the additional electron.
- This repulsion causes the outer electrons to spread out more, resulting in an increase in size.
- Therefore, I- will have the largest size among the three species.

3. **Analyzing I (Neutral Iodine Atom)**:
- The neutral iodine atom (I) has a balanced number of protons and electrons.
- It has a smaller size compared to I- because it does not have the extra electron that contributes to repulsion.
- Thus, the size of I is smaller than that of I-.

4. **Analyzing I+ (Iodine Cation)**:
- When iodine loses an electron to form I+, the number of electrons decreases, which reduces electron-electron repulsion.
- With less repulsion, the remaining electrons can be pulled closer to the nucleus, resulting in a decrease in size.
- Therefore, I+ will have the smallest size among the three species.

5. **Establishing the Order**:
- Based on the analysis:
- I- > I > I+
- This means the order of size from largest to smallest is I-, I, I+.

### Final Answer:
The size of the iodine species follows the order: **I- > I > I+**.