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
- Iodine (I) has 7 valence electrons. Since there are three iodine atoms, we start with \( 3 \times 7 = 21 \) valence electrons.
- The negative charge (\(-1\)) indicates that there is one additional electron. Therefore, the total number of valence electrons is \( 21 + 1 = 22 \).

### Step 2: Draw the Lewis Structure
- In the Lewis structure, we place one iodine atom in the center and the other two iodine atoms on the sides.
- Each of the two outer iodine atoms will form a single bond with the central iodine atom, using 2 electrons (1 bond = 2 electrons).
- This accounts for \( 2 \) of the \( 22 \) total electrons, leaving us with \( 22 - 2 = 20 \) electrons.

### Step 3: Distribute Remaining Electrons
- The central iodine atom will have 3 lone pairs (6 electrons) and will bond with the two outer iodine atoms.
- The remaining \( 20 - 6 = 14 \) electrons will be distributed as lone pairs on the outer iodine atoms.
- Each outer iodine atom will have 3 lone pairs (6 electrons) and 1 bond with the central iodine atom.

### Step 4: Count Bonding Electrons and Lone Pairs
- **Bonding Electrons**: There are 2 bonds (1 bond between each outer iodine and the central iodine), which means there are \( 2 \times 2 = 4 \) bonding electrons.
- **Lone Pairs**: The central iodine has 3 lone pairs (6 electrons), and each outer iodine has 3 lone pairs (6 electrons each). Therefore, the total number of lone pairs is \( 3 + 3 + 3 = 9 \) lone pairs.

### Conclusion
- The number of bonding electrons in \( I_3^- \) is **4**.
- The number of lone pairs in \( I_3^- \) is **9**.

Thus, the bonding electrons and lone pairs present in \( I_3^- \) are respectively **4 and 9**.

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