The bonding electrons and lone pairs present in `I_(3)^(-)` are respectively:

Options

A. 4.9
B. 2,9
C. 4,4
D. 9,9

Answer

To determine the number of bonding electrons and lone pairs in the ion \( I_3^- \), we can follow these steps:

### Step 1: Determine the Valence Electrons of Iodine
Iodine (I) is in Group 17 of the periodic table, which means it has 7 valence electrons. Since there are three iodine atoms in \( I_3^- \), we calculate the total valence electrons contributed by iodine:
- Total from 3 iodine atoms = \( 3 \times 7 = 21 \) electrons.

### Step 2: Account for the Negative Charge
The \( I_3^- \) ion has an extra electron due to its negative charge. Therefore, we add 1 more electron to the total:
- Total valence electrons = \( 21 + 1 = 22 \) electrons.

### Step 3: Draw the Lewis Structure
To draw the Lewis structure for \( I_3^- \):
1. Place the three iodine atoms in a line (I-I-I).
2. Connect the iodine atoms with single bonds. Each bond uses 2 electrons, so 2 bonds will use 4 electrons.
3. After forming the bonds, we have \( 22 - 4 = 18 \) electrons remaining.
4. Distribute the remaining electrons to satisfy the octet rule. Start by placing lone pairs around the outer iodine atoms.

### Step 4: Count the Bonding Electrons
In the Lewis structure:
- Each bond between the iodine atoms counts as bonding electrons. Since there are 2 bonds, the number of bonding electrons is:
- Bonding electrons = 4 (2 bonds × 2 electrons per bond).

### Step 5: Count the Lone Pairs
After distributing the remaining electrons:
- The central iodine atom will have 3 lone pairs (6 electrons).
- Each of the outer iodine atoms will have 3 lone pairs (6 electrons each).
- Total lone pairs = \( 3 (from central I) + 6 (from one outer I) + 6 (from another outer I) = 9 \) lone pairs.

### Final Answer
Thus, the bonding electrons and lone pairs in \( I_3^- \) are:
- Bonding electrons: 4
- Lone pairs: 9

### Summary
The bonding electrons and lone pairs present in \( I_3^- \) are respectively: **4 bonding electrons and 9 lone pairs.**

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